{ "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-2026-34585", "tracking": { "current_release_date": "2026-04-03T17:26:14.837171Z", "generator": { "date": "2026-02-17T15:00:00Z", "engine": { "name": "V.E.L.M.A", "version": "1.7" } }, "id": "CVE-2026-34585", "initial_release_date": "2026-03-31T22:26:13.122357Z", "revision_history": [ { "date": "2026-03-31T22:26:13.122357Z", "number": "1", "summary": "CVE created.| Source created.| CVE status created. (valid)| Description created for source.| CVSS created.| References created (3).| CWES updated (1)." }, { "date": "2026-03-31T22:26:14.974280Z", "number": "2", "summary": "NCSC Score created." }, { "date": "2026-03-31T22:40:08.979212Z", "number": "3", "summary": "Source created.| CVE status created. (valid)| Description created for source.| CVSS created.| Products connected (1).| References created (3).| CWES updated (1)." }, { "date": "2026-03-31T22:40:11.399365Z", "number": "4", "summary": "NCSC Score updated." }, { "date": "2026-04-01T01:03:17.636921Z", "number": "5", "summary": "Source created.| CVE status created. (valid)| Description created for source.| CVSS created.| References created (4).| CWES updated (1)." }, { "date": "2026-04-01T01:03:29.229682Z", "number": "6", "summary": "NCSC Score updated." }, { "date": "2026-04-01T07:50:17.669513Z", "number": "7", "summary": "NCSC Score updated." }, { "date": "2026-04-01T14:39:33.174199Z", "number": "8", "summary": "Unknown change." }, { "date": "2026-04-01T14:39:40.043902Z", "number": "9", "summary": "NCSC Score updated." }, { "date": "2026-04-01T15:06:26.773601Z", "number": "10", "summary": "Source connected.| CVE status created. (valid)| EPSS created." }, { "date": "2026-04-01T15:08:04.985385Z", "number": "11", "summary": "NCSC Score updated." }, { "date": "2026-04-03T17:26:10.636746Z", "number": "12", "summary": "Products connected (1).| Product Identifiers created (1).| Exploits created (1)." }, { "date": "2026-04-03T17:26:14.170422Z", "number": "13", "summary": "NCSC Score updated." } ], "status": "interim", "version": "13" } }, "product_tree": { "branches": [ { "branches": [ { "branches": [ { "category": "product_version_range", "name": "vers:unknown/<3.6.2", "product": { "name": "vers:unknown/<3.6.2", "product_id": "CSAFPID-5899391", "product_identification_helper": { "cpe": "cpe:2.3:a:b3log:siyuan:*:*:*:*:*:*:*:*" } } } ], "category": "product_name", "name": "siyuan" } ], "category": "vendor", "name": "B3log" }, { "branches": [ { "branches": [ { "category": "product_version_range", "name": "vers:unknown/<3.6.2", "product": { "name": "vers:unknown/<3.6.2", "product_id": "CSAFPID-5878158" } } ], "category": "product_name", "name": "siyuan" } ], "category": "vendor", "name": "siyuan-note" } ] }, "vulnerabilities": [ { "cve": "CVE-2026-34585", "cwe": { "id": "CWE-79", "name": "Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')" }, "notes": [ { "category": "description", "text": "SiYuan is a personal knowledge management system. Prior to version 3.6.2, a vulnerability allows crafted block attribute values to bypass server-side attribute escaping when an HTML entity is mixed with raw special characters. An attacker can embed a malicious IAL value inside a .sy document, package it as a .sy.zip, and have the victim import it through the normal Import -> SiYuan .sy.zip workflow. Once the note is opened, the malicious attribute breaks out of its original HTML context and injects an event handler, resulting in stored XSS. In the Electron desktop client, this XSS reaches remote code execution because injected JavaScript runs with access to Node/Electron APIs. This issue has been patched in version 3.6.2.", "title": "nvd - https://services.nvd.nist.gov/rest/json/cves/2.0?cveId=CVE-2026-34585" }, { "category": "description", "text": "SiYuan is a personal knowledge management system. Prior to version 3.6.2, a vulnerability allows crafted block attribute values to bypass server-side attribute escaping when an HTML entity is mixed with raw special characters. An attacker can embed a malicious IAL value inside a .sy document, package it as a .sy.zip, and have the victim import it through the normal Import -> SiYuan .sy.zip workflow. Once the note is opened, the malicious attribute breaks out of its original HTML context and injects an event handler, resulting in stored XSS. In the Electron desktop client, this XSS reaches remote code execution because injected JavaScript runs with access to Node/Electron APIs. This issue has been patched in version 3.6.2.", "title": "cveprojectv5 - https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/34xxx/CVE-2026-34585.json" }, { "category": "description", "text": "### Summary\nA vulnerability allows crafted block attribute values to bypass server-side attribute escaping when an HTML entity is mixed with raw special characters. An attacker can embed a malicious IAL value inside a `.sy` document, package it as a `.sy.zip`, and have the victim import it through the normal `Import -> SiYuan .sy.zip` workflow. Once the note is opened, the malicious attribute breaks out of its original HTML context and injects an event handler, resulting in stored XSS. In the Electron desktop client, this XSS reaches remote code execution because injected JavaScript runs with access to Node/Electron APIs.\n\n### Details\nThe issue is caused by a logic regression in `escapeNodeAttributeValues` in `kernel/filesys/tree.go`.\nPreviously, the escaping logic converted `node.KramdownIAL` with `parse.IAL2Map(...)` before deciding whether a value needed escaping. That conversion unescaped existing entities first, so mixed values such as:\n```\n&\" onmouseenter=\"alert('IAL-XSS')\n```\nwere still recognized as unsafe and escaped correctly.\nThe logic changed to inspect raw `KramdownIAL` values directly. The new `needsEscapeForValue` implementation returns `false` as soon as it sees any known entity such as `&`, `"`, `<`, or `>`. This means a value containing both an entity and an unescaped raw quote bypasses escaping entirely.\n\nThat bypass becomes exploitable because the renderer later inserts block IAL values directly into HTML attributes. A payload like:\n```\n&\" onmouseenter=\"require('child_process').exec('calc')\n```\ncan be rendered into HTML equivalent to:\n```\n
\n```\nThis creates a stored XSS condition. In SiYuan Desktop, the Electron renderer runs with Node.js integration available, so attacker-controlled JavaScript can invoke Node APIs directly. As a result, the issue is not limited to script execution in the page context and becomes arbitrary command execution on the victim’s machine.\n\nThe stored XSS path was validated by importing a crafted `.sy.zip` through the normal GUI and triggering JavaScript execution from the rendered block. Because the same injected JavaScript runs in the privileged Electron renderer, this is an RCE issue in the desktop client.\n\n### PoC\n1. Start SiYuan Desktop `v3.6.1`.\n2. Prepare a crafted `.sy.zip` containing a .sy document with a block IAL property such as:\n```\n\"title\": \"&\\\" onmouseenter=\\\"require('child_process').exec('calc')\"\n```\n3. In the UI, right-click any notebook.\n4. Select `Import -> SiYuan .sy.zip`.\n5. Import the crafted archive.\n6. Open the imported note.\n7. Move the mouse over the affected paragraph block.\n8. Observe that the injected JavaScript executes.\n9. On Windows, `calc.exe` launches, demonstrating arbitrary command execution.\n\n### Impact\nThis vulnerability allows an attacker to deliver a malicious `.sy.zip` file that executes attacker-controlled JavaScript after import. In the desktop application, that JavaScript runs with Node/Electron privileges and can execute arbitrary operating system commands under the victim’s account. This makes the bug equivalent to local code execution triggered by importing and opening attacker-supplied content.", "title": "github - https://api.github.com/advisories/GHSA-ff66-236v-p4fg" }, { "category": "other", "text": "0.00072", "title": "EPSS" }, { "category": "other", "text": "3.6", "title": "NCSC Score" }, { "category": "other", "text": "The value of the most recent CVSS (V3) score, Is related to an uncommon product vendor, Is related to (a version of) an uncommon product, The CVSS vector string contains A:N (Availability Impact: None), There is exploit data available from source Nvd", "title": "NCSC Score top decreasing factors" } ], "product_status": { "known_affected": [ "CSAFPID-5878158", "CSAFPID-5899391" ] }, "references": [ { "category": "external", "summary": "Source - nvd", "url": "https://services.nvd.nist.gov/rest/json/cves/2.0?cveId=CVE-2026-34585" }, { "category": "external", "summary": "Source - cveprojectv5", "url": "https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/34xxx/CVE-2026-34585.json" }, { "category": "external", "summary": "Source - github", "url": "https://api.github.com/advisories/GHSA-ff66-236v-p4fg" }, { "category": "external", "summary": "Source - first", "url": "https://api.first.org/data/v1/epss?limit=10000&offset=0" }, { "category": "external", "summary": "Reference - cveprojectv5; nvd", "url": "https://github.com/siyuan-note/siyuan/issues/17246" }, { "category": "external", "summary": "Reference - cveprojectv5; github; nvd", "url": "https://github.com/siyuan-note/siyuan/releases/tag/v3.6.2" }, { "category": "external", "summary": "Reference - cveprojectv5; github; nvd", "url": "https://github.com/siyuan-note/siyuan/security/advisories/GHSA-ff66-236v-p4fg" }, { "category": "external", "summary": "Reference - github", "url": "https://github.com/siyuan-note/siyuan/commit/918d1bd9f967d888f474f6764744a3d8cca4a501" }, { "category": "external", "summary": "Reference - github", "url": "https://github.com/advisories/GHSA-ff66-236v-p4fg" } ], "scores": [ { "cvss_v3": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H", "baseScore": 8.6, "baseSeverity": "HIGH" }, "products": [ "CSAFPID-5878158", "CSAFPID-5899391" ] } ], "title": "CVE-2026-34585" } ] }