{ "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-2026-100838", "tracking": { "current_release_date": "2026-09-30T17:39:52.835249Z", "generator": { "date": "2026-02-17T15:00:00Z", "engine": { "name": "V.E.L.M.A", "version": "1.7" } }, "id": "CVE-2026-100838", "initial_release_date": "2026-09-27T02:25:44.150474Z", "revision_history": [ { "date": "2026-09-27T02:25:44.150474Z", "number": "1", "summary": "CVE created.| Source created.| CVE status created. (valid)| Description created for source.| CVSS created.| References created (2).| CWES updated (1)." }, { "date": "2026-09-27T02:25:46.020950Z", "number": "2", "summary": "NCSC Score created." }, { "date": "2026-09-27T12:14:08.139175Z", "number": "3", "summary": "Source created.| CVE status created. (valid)| Description created for source.| CVSS created.| Products created (1).| References created (4).| CWES updated (1)." }, { "date": "2026-09-27T12:14:09.783661Z", "number": "4", "summary": "NCSC Score updated." }, { "date": "2026-09-27T15:15:09.676976Z", "number": "5", "summary": "EPSS created.| Unknown change." }, { "date": "2026-09-27T18:13:01.514954Z", "number": "6", "summary": "Source created.| CVE status created. (valid)| Description created for source.| CVSS created.| Products created (1).| References created (4).| CWES updated (1)." }, { "date": "2026-09-27T18:13:06.223450Z", "number": "7", "summary": "Source created.| CVE status created. (valid)| Description created for source.| References created (4)." }, { "date": "2026-09-27T18:13:10.010773Z", "number": "8", "summary": "NCSC Score updated." }, { "date": "2026-09-28T12:42:07.987789Z", "number": "9", "summary": "CVSS created.| CWES created (1).| Products created (2).| References created (2).| Description created for source.| Unknown change." }, { "date": "2026-09-28T12:42:11.436190Z", "number": "10", "summary": "NCSC Score updated." }, { "date": "2026-09-29T16:13:19.581323Z", "number": "11", "summary": "EPSS created.| Unknown change." }, { "date": "2026-09-29T18:31:24.441087Z", "number": "12", "summary": "NCSC Score updated." }, { "date": "2026-09-30T17:39:50.940356Z", "number": "13", "summary": "Unknown change." } ], "status": "interim", "version": "13" } }, "product_tree": { "branches": [ { "branches": [ { "branches": [ { "category": "product_version_range", "name": "vers:semver/1.19.1", "product": { "name": "vers:semver/1.19.1", "product_id": "CSAFPID-9478895" } }, { "category": "product_version_range", "name": "vers:semver/<1.19.1", "product": { "name": "vers:semver/<1.19.1", "product_id": "CSAFPID-9478896" } }, { "category": "product_version_range", "name": "vers:unknown/>=0|<1.19.1", "product": { "name": "vers:unknown/>=0|<1.19.1", "product_id": "CSAFPID-9475357" } }, { "category": "product_version_range", "name": "vers:unknown/v1.19.0", "product": { "name": "vers:unknown/v1.19.0", "product_id": "CSAFPID-9474623" } } ], "category": "product_name", "name": "contrast" } ], "category": "vendor", "name": "edgelesssys" } ] }, "vulnerabilities": [ { "cve": "CVE-2026-100838", "cwe": { "id": "CWE-59", "name": "Improper Link Resolution Before File Access ('Link Following')" }, "notes": [ { "category": "description", "text": "Contrast is a confidential-computing runtime for Kubernetes. In versions before 1.19.1, the Kata agent policies generated by the Contrast CLI contained a flaw in the CopyFile verification that allowed arbitrary writes to the guest root filesystem. A malicious process on the untrusted host able to connect to the Kata agent VSOCK could issue a series of CopyFile requests to overwrite security-critical files in the guest or trick the workload into disclosing sensitive data, effectively amounting to a full guest takeover. Users unable to upgrade can apply an equivalent rego policy fix passed to 'contrast generate --policy'.", "title": "cveprojectv5 - https://www.cve.org/CVERecord?id=CVE-2026-100838" }, { "category": "description", "text": "Contrast is a confidential-computing runtime for Kubernetes. In versions before 1.19.1, the Kata agent policies generated by the Contrast CLI contained a flaw in the CopyFile verification that allowed arbitrary writes to the guest root filesystem. A malicious process on the untrusted host able to connect to the Kata agent VSOCK could issue a series of CopyFile requests to overwrite security-critical files in the guest or trick the workload into disclosing sensitive data, effectively amounting to a full guest takeover. Users unable to upgrade can apply an equivalent rego policy fix passed to 'contrast generate --policy'.", "title": "nvd - https://nvd.nist.gov/vuln/detail/CVE-2026-100838" }, { "category": "description", "text": "Contrast is a confidential-computing runtime for Kubernetes. In versions before 1.19.1, the Kata agent policies generated by the Contrast CLI contained a flaw in the CopyFile verification that allowed arbitrary writes to the guest root filesystem. A malicious process on the untrusted host able to connect to the Kata agent VSOCK could issue a series of CopyFile requests to overwrite security-critical files in the guest or trick the workload into disclosing sensitive data, effectively amounting to a full guest takeover. Users unable to upgrade can apply an equivalent rego policy fix passed to 'contrast generate --policy'.", "title": "osv - https://www.googleapis.com/download/storage/v1/b/osv-vulnerabilities/o/GIT%2FCVE-2026-100838.json?alt=media" }, { "category": "description", "text": "### Impact\n\nThe [Kata agent policies](https://docs.edgeless.systems/contrast/architecture/components/policies) generated by the Contrast CLI had an issue in the `CopyFile` verification, which allowed arbitrary writes to the guest root filesytem. A malicious process on the host with the capability to connect to the Kata agent VSOCK could connect to the agent and issue a series of `CopyFile` requests to overwrite security-critical files or trick the workload into disclosing sensitive data, which effectively amounts to a full guest takeover.\n\n### Patches\n\nThis issue has been patched in Contrast v1.19.1.\n\nNote that this fix does not change the fact that host-provided content is generally not trustworthy, as documented.\n\n### Workarounds\n\nIf upgrading is not possible, users can implement the fix in rego and pass it to `contrast generate --policy`. The rego-only fix is a bit trickier than the patch, because the data to check is binary. See the references for details.\n\n### Resources\n\n* Upstream GHSA: https://github.com/kata-containers/kata-containers/security/advisories/GHSA-q49m-57vm-c8cc\n* Alternative policy-only fix: https://gist.github.com/burgerdev/304dd0ab0fff1665b7c27e18a30cf96e", "title": "osv - https://www.googleapis.com/download/storage/v1/b/osv-vulnerabilities/o/Go%2FGHSA-rh99-wc69-c255.json?alt=media" }, { "category": "description", "text": "Contras Affected by CopyFile Policy Subversion via Symlinks in github.com/edgelesssys/contrast", "title": "osv - https://www.googleapis.com/download/storage/v1/b/osv-vulnerabilities/o/Go%2FGO-2026-5624.json?alt=media" }, { "category": "other", "text": "0.00221", "title": "EPSS" }, { "category": "other", "text": "CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X", "title": "CVSSV4" }, { "category": "other", "text": "8.6", "title": "CVSSV4 base score" }, { "category": "other", "text": "4.0", "title": "NCSC Score" }, { "category": "other", "text": "There is cwe data available from source Nvd, The value of the most recent CVSS (V3) score", "title": "NCSC Score top decreasing factors" } ], "product_status": { "known_affected": [ "CSAFPID-9474623", "CSAFPID-9475357", "CSAFPID-9478896" ], "known_not_affected": [ "CSAFPID-9478895" ] }, "references": [ { "category": "external", "summary": "Source - osv", "url": "https://www.googleapis.com/download/storage/v1/b/osv-vulnerabilities/o/Go%2FGHSA-rh99-wc69-c255.json?alt=media" }, { "category": "external", "summary": "Source - osv", "url": "https://www.googleapis.com/download/storage/v1/b/osv-vulnerabilities/o/Go%2FGO-2026-5624.json?alt=media" }, { "category": "external", "summary": "Source - nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-100838" }, { "category": "external", "summary": "Source - ncscclear", "url": "https://vulnerabilities.ncsc.nl/manual/CVE-2026-100838" }, { "category": "external", "summary": "Source - osv", "url": "https://www.googleapis.com/download/storage/v1/b/osv-vulnerabilities/o/GIT%2FCVE-2026-100838.json?alt=media" }, { "category": "external", "summary": "Source - first", "url": "https://api.first.org/data/v1/epss" }, { "category": "external", "summary": "Source - cveprojectv5", "url": "https://www.cve.org/CVERecord?id=CVE-2026-100838" }, { "category": "external", "summary": "Reference - cveprojectv5; nvd; osv", "url": "https://github.com/edgelesssys/contrast/security/advisories/GHSA-rh99-wc69-c255" }, { "category": "external", "summary": "Reference - cveprojectv5; nvd; osv", "url": "https://www.vulncheck.com/advisories/contrast-before-1.19.1-copyfile-policy-symlink-subversion" }, { "category": "external", "summary": "Reference - osv", "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/100xxx/CVE-2026-100838.json" }, { "category": "external", "summary": "Reference - osv", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-100838" }, { "category": "external", "summary": "Reference - osv", "url": "https://gist.github.com/burgerdev/304dd0ab0fff1665b7c27e18a30cf96e" }, { "category": "external", "summary": "Reference - osv", "url": "https://github.com/edgelesssys/contrast/releases/tag/v1.19.1" }, { "category": "external", "summary": "Reference - osv", "url": "https://github.com/kata-containers/kata-containers/security/advisories/GHSA-q49m-57vm-c8cc" } ], "scores": [ { "cvss_v3": { "version": "3.1", "vectorString": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N", "baseScore": 8.1, "baseSeverity": "HIGH" }, "products": [ "CSAFPID-9474623", "CSAFPID-9475357", "CSAFPID-9478896" ] } ], "title": "CVE-2026-100838" } ] }