{
"document": {
"category": "csaf_base",
"csaf_version": "2.0",
"distribution": {
"tlp": {
"label": "WHITE"
}
},
"lang": "en",
"notes": [
{
"category": "legal_disclaimer",
"text": "The Netherlands Cyber Security Center (henceforth: NCSC-NL) maintains this portal to enhance access to its information and vulnerabilities. The use of this information is subject to the following terms and conditions:\n\nThe vulnerabilities disclosed in this portal are gathered by NCSC-NL from a variety of open sources, which the user can retrieve from other platforms. NCSC-NL makes every reasonable effort to ensure that the content of this portal is kept up to date, and that it is accurate and complete. Nevertheless, NCSC-NL cannot entirely rule out the possibility of errors, and therefore cannot give any warranty in respect of its completeness, accuracy or real-time keeping up-to-date. NCSC-NL does not control nor guarantee the accuracy, relevance, timeliness or completeness of information obtained from these external sources. The vulnerabilities disclosed in this portal are intended solely for the convenience of professional parties to take appropriate measures to manage the risks posed to the cybersecurity. No rights can be derived from the information provided therein.\n\nNCSC-NL and the Kingdom of the Netherlands assume no legal liability or responsibility for any damage resulting from either the use or inability of use of the vulnerabilities disclosed in this portal. This includes damage resulting from the inaccuracy of incompleteness of the information contained in it.\nThe information on this page is subject to Dutch law. All disputes related to or arising from the use of this portal regarding the disclosure of vulnerabilities will be submitted to the competent court in The Hague. This choice of means also applies to the court in summary proceedings."
}
],
"publisher": {
"category": "coordinator",
"contact_details": "cert@ncsc.nl",
"name": "National Cyber Security Centre",
"namespace": "https://www.ncsc.nl/"
},
"title": "CVE-2026-33081",
"tracking": {
"current_release_date": "2026-03-25T18:13:45.514266Z",
"generator": {
"date": "2026-02-17T15:00:00Z",
"engine": {
"name": "V.E.L.M.A",
"version": "1.7"
}
},
"id": "CVE-2026-33081",
"initial_release_date": "2026-03-18T17:08:15.311063Z",
"revision_history": [
{
"date": "2026-03-18T17:08:15.311063Z",
"number": "1",
"summary": "CVE created.| Source created.| CVE status created. (valid)| Description created for source.| CVSS created.| References created (2).| CWES updated (1)."
},
{
"date": "2026-03-18T17:08:27.995760Z",
"number": "2",
"summary": "NCSC Score created."
},
{
"date": "2026-03-19T11:40:06.068585Z",
"number": "3",
"summary": "Source created.| CVE status created. (valid)| Description created for source.| CVSS created.| References created (2).| CWES updated (1)."
},
{
"date": "2026-03-20T18:28:48.970185Z",
"number": "4",
"summary": "Source created.| CVE status created. (valid)| Description created for source.| CVSS created.| Products created (1).| References created (2).| CWES updated (1)."
},
{
"date": "2026-03-20T18:28:52.227857Z",
"number": "5",
"summary": "NCSC Score updated."
},
{
"date": "2026-03-20T18:28:52.994597Z",
"number": "6",
"summary": "Source created.| CVE status created. (valid)| Description created for source.| CVSS created.| References created (2).| CWES updated (1)."
},
{
"date": "2026-03-20T18:28:56.944752Z",
"number": "7",
"summary": "NCSC Score updated."
},
{
"date": "2026-03-20T21:38:49.950954Z",
"number": "8",
"summary": "Unknown change."
},
{
"date": "2026-03-20T21:41:33.233662Z",
"number": "9",
"summary": "References created (2)."
},
{
"date": "2026-03-20T21:59:00.771057Z",
"number": "10",
"summary": "Source connected.| CVE status created. (valid)| EPSS created."
},
{
"date": "2026-03-20T21:59:04.172290Z",
"number": "11",
"summary": "NCSC Score updated."
},
{
"date": "2026-03-21T13:47:17.799624Z",
"number": "12",
"summary": "References removed (2)."
},
{
"date": "2026-03-22T00:51:43.647281Z",
"number": "13",
"summary": "References created (2)."
},
{
"date": "2026-03-22T11:24:47.072171Z",
"number": "14",
"summary": "References removed (2)."
},
{
"date": "2026-03-23T00:53:53.786137Z",
"number": "15",
"summary": "References created (2)."
},
{
"date": "2026-03-23T05:15:50.773411Z",
"number": "16",
"summary": "References removed (2)."
},
{
"date": "2026-03-24T02:15:45.892381Z",
"number": "17",
"summary": "Products connected (1).| Product Identifiers created (1).| Exploits created (1)."
},
{
"date": "2026-03-24T02:15:50.966436Z",
"number": "18",
"summary": "NCSC Score updated."
},
{
"date": "2026-03-24T20:56:11.038618Z",
"number": "19",
"summary": "References created (2)."
},
{
"date": "2026-03-24T20:57:35.161658Z",
"number": "20",
"summary": "NCSC Score updated."
},
{
"date": "2026-03-25T18:13:02.512127Z",
"number": "21",
"summary": "Source created.| CVE status created. (valid)| Description created for source.| CVSS created.| Products created (1).| References created (3).| CWES updated (1)."
},
{
"date": "2026-03-25T18:13:04.955161Z",
"number": "22",
"summary": "NCSC Score updated."
},
{
"date": "2026-03-25T18:13:44.810662Z",
"number": "23",
"summary": "Source created.| CVE status created. (valid)| Description created for source.| References created (3)."
}
],
"status": "interim",
"version": "23"
}
},
"product_tree": {
"branches": [
{
"branches": [
{
"branches": [
{
"category": "product_version_range",
"name": "vers:unknown/<0.8.3",
"product": {
"name": "vers:unknown/<0.8.3",
"product_id": "CSAFPID-5874575",
"product_identification_helper": {
"cpe": "cpe:2.3:a:pinchtab:pinchtab:*:*:*:*:*:*:*:*"
}
}
},
{
"category": "product_version_range",
"name": "vers:unknown/>=0|<0.8.3",
"product": {
"name": "vers:unknown/>=0|<0.8.3",
"product_id": "CSAFPID-5907213"
}
}
],
"category": "product_name",
"name": "pinchtab"
}
],
"category": "vendor",
"name": "pinchtab"
}
]
},
"vulnerabilities": [
{
"cve": "CVE-2026-33081",
"cwe": {
"id": "CWE-918",
"name": "Server-Side Request Forgery (SSRF)"
},
"notes": [
{
"category": "description",
"text": "### **The /download endpoint validates only the initial URL provided by the user using validateDownloadURL() to prevent requests to internal or private network addresses.**\n\nExploitation requires \\security.allowDownload=true`, which is disabled by default.`\n\nHowever, pages loaded by the embedded Chromium browser can trigger additional browser-side requests (for example, JavaScript redirects, navigations, or resource requests) after the initial validation step.\n\nBecause the validation is only applied to the initial URL and not to subsequent browser-issued request targets, an attacker-controlled page can cause the browser to issue requests to internal network services reachable from the PinchTab host.\n\nThis results in a blind Server-Side Request Forgery (SSRF) condition in which internal-only services may be accessed and state-changing endpoints may be triggered without returning the response body to the attacker.\n\n\n### **Steps to Reproduce:**\n\n**Environment Setup**\nTarget: PinchTab server (tested on v0.8.x, v0.7.x)\nAttacker-controlled server: Publicly accessible (e.g., via ngrok) [attacker.py](https://github.com/user-attachments/files/26013554/att.py)\nInternal service: Runs on the same host as PinchTab and is not externally accessible [internal_service.py](https://github.com/user-attachments/files/26013551/internal.py)\n\n**1. Start a Local Internal Service (Victim Side)**\n\nRun a simple HTTP service bound to localhost: [internal_service.py](https://github.com/user-attachments/files/26013551/internal.py)\n \n python internal_service.py\n \n #Example behavior of internal_service.py:\n #Listens on 127.0.0.1:1337\n #Exposes endpoint /increment\n #Increments a counter and logs requests\n \n #Expected output when accessed:\n #COUNTER INCREMENTED: 1\n #COUNTER INCREMENTED: 2\n\n**2. Host an Attacker-Controlled Page (Attacker side)**\n\nDeploy a malicious HTML page that redirects to the internal service: [attacker.py](https://github.com/user-attachments/files/26013554/att.py)\n\n \n \n \n \n \nHost this page on a publicly accessible server (e.g., using ngrok): https://fcb8-180-149-93-3.ngrok-free.app\n\n\n**3. Trigger the Vulnerable Endpoint (Attacker side)**\n\nSend a request to the PinchTab /download endpoint:\n\n curl \"http://[server-ip]:9867/download?url=https://fcb8-180-149-93-3.ngrok-free.app\"\n\nIf a server token is configured, the request must include valid authentication.\n\n**4. Observe Server-Side Request to Localhost**\n\nWhen PinchTab processes the request:\n1. It launches a headless Chromium instance\n2. The browser loads the attacker-controlled page\n3. JavaScript executes within the browser\n4. The browser redirects to: http://127.0.0.1:1337/increment\n\n\n**5. Verify the Impact**\n\nCheck the output of internal_service.py:\n ![\"proof\"](\"https://github.com/user-attachments/assets/cf00e3e6-71c6-44ae-83b0-ed819f19ee9a\")
\n\nCOUNTER INCREMENTED: 1\n ![\"proof_incremented\"](\"https://github.com/user-attachments/assets/98281b8e-221b-4e76-a10b-1b2335d08c61\")
\n\n**This confirms that the request originated from the PinchTab host and that an attacker can successfully access localhost-only internal services via the browser, despite the initial URL validation.**\n\n\n### **Impact**\nThis vulnerability allows an attacker to bypass the /download URL validation and cause the embedded Chromium browser to make requests to internal network services. By hosting a page that performs a redirect after the initial validation, an attacker can force the browser to access resources such as 127.0.0.1 or other private network addresses reachable from the PinchTab host.\n\nAlthough the response is not returned to the attacker (blind SSRF), this behavior can still be used to interact with internal services and trigger state-changing endpoints. In environments where sensitive services or cloud metadata endpoints are accessible from the host, this could lead to more serious security impact.\n\n### **Mitigation**\nApply the same URL safety policy to every browser-issued request in the `/download` flow, not only the initial user-supplied URL, and block requests to loopback, private, link-local, and other non-public network ranges inside the Chromium browser context.",
"title": "github - https://github.com/advisories/GHSA-qwxp-6qf9-wr4m"
},
{
"category": "description",
"text": "### **The /download endpoint validates only the initial URL provided by the user using validateDownloadURL() to prevent requests to internal or private network addresses.**\n\nExploitation requires \\security.allowDownload=true`, which is disabled by default.`\n\nHowever, pages loaded by the embedded Chromium browser can trigger additional browser-side requests (for example, JavaScript redirects, navigations, or resource requests) after the initial validation step.\n\nBecause the validation is only applied to the initial URL and not to subsequent browser-issued request targets, an attacker-controlled page can cause the browser to issue requests to internal network services reachable from the PinchTab host.\n\nThis results in a blind Server-Side Request Forgery (SSRF) condition in which internal-only services may be accessed and state-changing endpoints may be triggered without returning the response body to the attacker.\n\n\n### **Steps to Reproduce:**\n\n**Environment Setup**\nTarget: PinchTab server (tested on v0.8.x, v0.7.x)\nAttacker-controlled server: Publicly accessible (e.g., via ngrok) [attacker.py](https://github.com/user-attachments/files/26013554/att.py)\nInternal service: Runs on the same host as PinchTab and is not externally accessible [internal_service.py](https://github.com/user-attachments/files/26013551/internal.py)\n\n**1. Start a Local Internal Service (Victim Side)**\n\nRun a simple HTTP service bound to localhost: [internal_service.py](https://github.com/user-attachments/files/26013551/internal.py)\n \n python internal_service.py\n \n #Example behavior of internal_service.py:\n #Listens on 127.0.0.1:1337\n #Exposes endpoint /increment\n #Increments a counter and logs requests\n \n #Expected output when accessed:\n #COUNTER INCREMENTED: 1\n #COUNTER INCREMENTED: 2\n\n**2. Host an Attacker-Controlled Page (Attacker side)**\n\nDeploy a malicious HTML page that redirects to the internal service: [attacker.py](https://github.com/user-attachments/files/26013554/att.py)\n\n \n \n \n \n \nHost this page on a publicly accessible server (e.g., using ngrok): https://fcb8-180-149-93-3.ngrok-free.app\n\n\n**3. Trigger the Vulnerable Endpoint (Attacker side)**\n\nSend a request to the PinchTab /download endpoint:\n\n curl \"http://[server-ip]:9867/download?url=https://fcb8-180-149-93-3.ngrok-free.app\"\n\nIf a server token is configured, the request must include valid authentication.\n\n**4. Observe Server-Side Request to Localhost**\n\nWhen PinchTab processes the request:\n1. It launches a headless Chromium instance\n2. The browser loads the attacker-controlled page\n3. JavaScript executes within the browser\n4. The browser redirects to: http://127.0.0.1:1337/increment\n\n\n**5. Verify the Impact**\n\nCheck the output of internal_service.py:\n \n\nCOUNTER INCREMENTED: 1\n \n\n**This confirms that the request originated from the PinchTab host and that an attacker can successfully access localhost-only internal services via the browser, despite the initial URL validation.**\n\n\n### **Impact**\nThis vulnerability allows an attacker to bypass the /download URL validation and cause the embedded Chromium browser to make requests to internal network services. By hosting a page that performs a redirect after the initial validation, an attacker can force the browser to access resources such as 127.0.0.1 or other private network addresses reachable from the PinchTab host.\n\nAlthough the response is not returned to the attacker (blind SSRF), this behavior can still be used to interact with internal services and trigger state-changing endpoints. In environments where sensitive services or cloud metadata endpoints are accessible from the host, this could lead to more serious security impact.\n\n### **Mitigation**\nApply the same URL safety policy to every browser-issued request in the `/download` flow, not only the initial user-supplied URL, and block requests to loopback, private, link-local, and other non-public network ranges inside the Chromium browser context.",
"title": "github - https://api.github.com/advisories/GHSA-qwxp-6qf9-wr4m"
},
{
"category": "description",
"text": "PinchTab is a standalone HTTP server that gives AI agents direct control over a Chrome browser. Versions 0.8.2 and below have a Blind SSRF vulnerability in the /download endpoint. The validateDownloadURL() function only checks the initial user-supplied URL, but the embedded Chromium browser can follow attacker-controlled redirects/navigations to internal network addresses after validation. Exploitation requires security.allowDownload=true (disabled by default), limiting real-world impact. An attacker-controlled page can use JavaScript redirects or resource requests to make the browser reach internal services from the PinchTab host, resulting in a blind Server-Side Request Forgery (SSRF) condition against internal-only services. The issue has been patched in version 0.8.3.",
"title": "cveprojectv5 - https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/33xxx/CVE-2026-33081.json"
},
{
"category": "description",
"text": "PinchTab is a standalone HTTP server that gives AI agents direct control over a Chrome browser. Versions 0.8.2 and below have a Blind SSRF vulnerability in the /download endpoint. The validateDownloadURL() function only checks the initial user-supplied URL, but the embedded Chromium browser can follow attacker-controlled redirects/navigations to internal network addresses after validation. Exploitation requires security.allowDownload=true (disabled by default), limiting real-world impact. An attacker-controlled page can use JavaScript redirects or resource requests to make the browser reach internal services from the PinchTab host, resulting in a blind Server-Side Request Forgery (SSRF) condition against internal-only services. The issue has been patched in version 0.8.3.",
"title": "nvd - https://services.nvd.nist.gov/rest/json/cves/2.0?cveId=CVE-2026-33081"
},
{
"category": "description",
"text": "### **The /download endpoint validates only the initial URL provided by the user using validateDownloadURL() to prevent requests to internal or private network addresses.**\n\nExploitation requires \\security.allowDownload=true`, which is disabled by default.`\n\nHowever, pages loaded by the embedded Chromium browser can trigger additional browser-side requests (for example, JavaScript redirects, navigations, or resource requests) after the initial validation step.\n\nBecause the validation is only applied to the initial URL and not to subsequent browser-issued request targets, an attacker-controlled page can cause the browser to issue requests to internal network services reachable from the PinchTab host.\n\nThis results in a blind Server-Side Request Forgery (SSRF) condition in which internal-only services may be accessed and state-changing endpoints may be triggered without returning the response body to the attacker.\n\n\n### **Steps to Reproduce:**\n\n**Environment Setup**\nTarget: PinchTab server (tested on v0.8.x, v0.7.x)\nAttacker-controlled server: Publicly accessible (e.g., via ngrok) [attacker.py](https://github.com/user-attachments/files/26013554/att.py)\nInternal service: Runs on the same host as PinchTab and is not externally accessible [internal_service.py](https://github.com/user-attachments/files/26013551/internal.py)\n\n**1. Start a Local Internal Service (Victim Side)**\n\nRun a simple HTTP service bound to localhost: [internal_service.py](https://github.com/user-attachments/files/26013551/internal.py)\n \n python internal_service.py\n \n #Example behavior of internal_service.py:\n #Listens on 127.0.0.1:1337\n #Exposes endpoint /increment\n #Increments a counter and logs requests\n \n #Expected output when accessed:\n #COUNTER INCREMENTED: 1\n #COUNTER INCREMENTED: 2\n\n**2. Host an Attacker-Controlled Page (Attacker side)**\n\nDeploy a malicious HTML page that redirects to the internal service: [attacker.py](https://github.com/user-attachments/files/26013554/att.py)\n\n \n \n \n \n \nHost this page on a publicly accessible server (e.g., using ngrok): https://fcb8-180-149-93-3.ngrok-free.app\n\n\n**3. Trigger the Vulnerable Endpoint (Attacker side)**\n\nSend a request to the PinchTab /download endpoint:\n\n curl \"http://[server-ip]:9867/download?url=https://fcb8-180-149-93-3.ngrok-free.app\"\n\nIf a server token is configured, the request must include valid authentication.\n\n**4. Observe Server-Side Request to Localhost**\n\nWhen PinchTab processes the request:\n1. It launches a headless Chromium instance\n2. The browser loads the attacker-controlled page\n3. JavaScript executes within the browser\n4. The browser redirects to: http://127.0.0.1:1337/increment\n\n\n**5. Verify the Impact**\n\nCheck the output of internal_service.py:\n \n\nCOUNTER INCREMENTED: 1\n \n\n**This confirms that the request originated from the PinchTab host and that an attacker can successfully access localhost-only internal services via the browser, despite the initial URL validation.**\n\n\n### **Impact**\nThis vulnerability allows an attacker to bypass the /download URL validation and cause the embedded Chromium browser to make requests to internal network services. By hosting a page that performs a redirect after the initial validation, an attacker can force the browser to access resources such as 127.0.0.1 or other private network addresses reachable from the PinchTab host.\n\nAlthough the response is not returned to the attacker (blind SSRF), this behavior can still be used to interact with internal services and trigger state-changing endpoints. In environments where sensitive services or cloud metadata endpoints are accessible from the host, this could lead to more serious security impact.\n\n### **Mitigation**\nApply the same URL safety policy to every browser-issued request in the `/download` flow, not only the initial user-supplied URL, and block requests to loopback, private, link-local, and other non-public network ranges inside the Chromium browser context.",
"title": "osv - https://www.googleapis.com/download/storage/v1/b/osv-vulnerabilities/o/Go%2FGHSA-qwxp-6qf9-wr4m.json?alt=media"
},
{
"category": "description",
"text": "PinchTab has a Blind SSRF via browser-side redirect bypass in /download URL validation in github.com/pinchtab/pinchtab",
"title": "osv - https://www.googleapis.com/download/storage/v1/b/osv-vulnerabilities/o/Go%2FGO-2026-4748.json?alt=media"
},
{
"category": "other",
"text": "0.00028",
"title": "EPSS"
},
{
"category": "other",
"text": "3.6",
"title": "NCSC Score"
},
{
"category": "other",
"text": "The value of the most recent EPSS score, Exploit code publicly available, There is exploit data available from source Nvd",
"title": "NCSC Score top decreasing factors"
}
],
"product_status": {
"known_affected": [
"CSAFPID-5874575",
"CSAFPID-5907213"
]
},
"references": [
{
"category": "external",
"summary": "Source - github",
"url": "https://github.com/advisories/GHSA-qwxp-6qf9-wr4m"
},
{
"category": "external",
"summary": "Source raw - github",
"url": "https://api.github.com/advisories/GHSA-qwxp-6qf9-wr4m"
},
{
"category": "external",
"summary": "Source - github",
"url": "https://api.github.com/advisories/GHSA-qwxp-6qf9-wr4m"
},
{
"category": "external",
"summary": "Source - cveprojectv5",
"url": "https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/33xxx/CVE-2026-33081.json"
},
{
"category": "external",
"summary": "Source - nvd",
"url": "https://services.nvd.nist.gov/rest/json/cves/2.0?cveId=CVE-2026-33081"
},
{
"category": "external",
"summary": "Source - first",
"url": "https://api.first.org/data/v1/epss?limit=10000&offset=0"
},
{
"category": "external",
"summary": "Source - osv",
"url": "https://www.googleapis.com/download/storage/v1/b/osv-vulnerabilities/o/Go%2FGHSA-qwxp-6qf9-wr4m.json?alt=media"
},
{
"category": "external",
"summary": "Source - osv",
"url": "https://www.googleapis.com/download/storage/v1/b/osv-vulnerabilities/o/Go%2FGO-2026-4748.json?alt=media"
},
{
"category": "external",
"summary": "Reference - cveprojectv5; github; nvd; osv",
"url": "https://github.com/pinchtab/pinchtab/security/advisories/GHSA-qwxp-6qf9-wr4m"
},
{
"category": "external",
"summary": "Reference - github",
"url": "https://github.com/advisories/GHSA-qwxp-6qf9-wr4m"
},
{
"category": "external",
"summary": "Reference - cveprojectv5; github; nvd; osv",
"url": "https://github.com/pinchtab/pinchtab/releases/tag/v0.8.3"
},
{
"category": "external",
"summary": "Reference - github; osv",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-33081"
}
],
"scores": [
{
"cvss_v3": {
"version": "3.1",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N",
"baseScore": 5.8,
"baseSeverity": "MEDIUM"
},
"products": [
"CSAFPID-5874575",
"CSAFPID-5907213"
]
}
],
"title": "CVE-2026-33081"
}
]
}