{"id":"CVE-2026-100838","aliases":["EUVD-2026-87850","GHSA-h734-rggh-79xq","GHSA-rh99-wc69-c255","GO-2026-5624"],"status":"published","title":"Contrast before 1.19.1 CopyFile Policy Symlink Subversion","description":"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'.","severity":{"version":"4.0","score":8.6,"vector":"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","level":"high","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-12","score":0.00221,"percentile":0.12799,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-59"],"published":"2026-04-30T20:57:17Z","modified":"2026-10-28T02:30:35Z","fixes":[{"ecosystem":"Go","package":"github.com/edgelesssys/contrast","fixed_in":["1.19.1"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"Go","package":"github.com/edgelesssys/contrast","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.19.1"}]}]},{"source":"osv","ecosystem":"Go","package":"github.com/edgelesssys/contrast","ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"1.19.1"}]}]},{"source":"osv","ecosystem":"Go","package":"github.com/edgelesssys/contrast","ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"1.19.1"}]}]}],"products":[{"vendor":"edgelesssys","product":"contrast"}],"references":[{"url":"https://github.com/edgelesssys/contrast/security/advisories/GHSA-rh99-wc69-c255","tags":["vendor-advisory","advisory","web"]},{"url":"https://www.vulncheck.com/advisories/contrast-before-1.19.1-copyfile-policy-symlink-subversion","tags":["third-party-advisory","advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-100838","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-h734-rggh-79xq"},{"url":"https://github.com/kata-containers/kata-containers/security/advisories/GHSA-q49m-57vm-c8cc","tags":["web"]},{"url":"https://gist.github.com/burgerdev/304dd0ab0fff1665b7c27e18a30cf96e","tags":["web"]},{"url":"https://github.com/edgelesssys/contrast/releases/tag/v1.19.1","tags":["web"]},{"url":"https://github.com/advisories/GHSA-rh99-wc69-c255"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/100xxx/CVE-2026-100838.json","tags":["advisory"]},{"url":"https://github.com/edgelesssys/contrast","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2026-100838","title":"Contrast before 1.19.1 CopyFile Policy Symlink Subversion","description":"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'.","status":"published","published":"2026-09-27T01:28:35.498Z","modified":"2026-10-08T15:22:00.652Z","cvss":[{"version":"4.0","score":8.6,"vector":"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","level":"high","assessor":"cna"},{"version":"3.1","score":8.1,"vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N","level":"high","assessor":"cna"}],"cwes":["CWE-59"],"updated_at":"2026-11-02T14:20:06.925367Z"}],"euvd":[{"id":"EUVD-2026-87850","description":"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'.","status":"published","published":"2026-09-27T01:28:35Z","modified":"2026-10-08T15:22:00Z","cvss":[{"version":"4.0","score":8.6,"vector":"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","level":"high"}],"updated_at":"2026-11-02T17:27:32.18003Z"}],"ghsa":[{"id":"GHSA-h734-rggh-79xq","title":"Contrast is a confidential-computing runtime for Kubernetes. In versions before 1.19.1, the Kata...","description":"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'.","status":"published","published":"2026-09-27T03:31:04Z","modified":"2026-09-27T03:31:12Z","cvss":[{"version":"4.0","score":8.6,"vector":"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","level":"high"},{"version":"3.1","score":8.1,"vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N","level":"high"}],"cwes":["CWE-59"],"updated_at":"2026-11-02T15:12:30.689958Z"},{"id":"GHSA-rh99-wc69-c255","title":"Contras Affected by CopyFile Policy Subversion via Symlinks","description":"### 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","status":"published","published":"2026-04-30T20:57:17Z","modified":"2026-04-30T20:57:19Z","cvss":[{"version":"3.1","score":8.1,"vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N","level":"high"}],"cwes":["CWE-59"],"updated_at":"2026-11-02T14:39:59.776263Z"}],"nvd":[{"id":"CVE-2026-100838","description":"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'.","status":"published","published":"2026-09-27T02:17:22.083Z","modified":"2026-10-08T16:16:59.643Z","cvss":[{"version":"4.0","score":8.6,"vector":"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","level":"high","assessor":"secondary"},{"version":"3.1","score":8.1,"vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N","level":"high","assessor":"secondary"}],"cwes":["CWE-59"],"updated_at":"2026-11-02T14:12:52.081323Z"}],"osv":[{"id":"CVE-2026-100838","title":"Contrast before 1.19.1 CopyFile Policy Symlink Subversion","description":"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'.","status":"published","published":"2026-09-27T01:28:35.498Z","modified":"2026-10-28T02:30:35.91215005Z","cvss":[{"version":"4.0","score":8.6,"vector":"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","level":"high"}],"cwes":["CWE-59"],"updated_at":"2026-11-02T15:44:53.83521Z"},{"id":"GHSA-rh99-wc69-c255","title":"Contras Affected by CopyFile Policy Subversion via Symlinks","description":"### 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","status":"published","published":"2026-04-30T20:57:17Z","modified":"2026-09-27T11:55:41.24110747Z","cvss":[{"version":"3.1","score":8.1,"vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N","level":"high"}],"cwes":["CWE-59"],"updated_at":"2026-11-02T15:46:55.877614Z"},{"id":"GO-2026-5624","title":"Contras Affected by CopyFile Policy Subversion via Symlinks in github.com/edgelesssys/contrast","description":"Contras Affected by CopyFile Policy Subversion via Symlinks in github.com/edgelesssys/contrast","status":"published","published":"2026-06-25T22:34:34Z","modified":"2026-09-27T11:55:41.24110747Z","updated_at":"2026-11-02T15:47:02.838915Z"}]}}