{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-96808", "assignerOrgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca", "state": "PUBLISHED", "assignerShortName": "mitre", "dateReserved": "2026-09-23T16:58:36.801Z", "datePublished": "2026-09-23T16:58:37.139Z", "dateUpdated": "2026-09-23T16:58:37.139Z"}, "containers": {"cna": {"affected": [{"defaultStatus": "unaffected", "platforms": ["Linux"], "product": "Flatpak", "programFiles": ["revokefs/writer.c"], "repo": "https://github.com/flatpak/flatpak", "vendor": "Flatpak", "versions": [{"lessThan": "1.18.1", "status": "affected", "version": "0", "versionType": "semver"}]}], "descriptions": [{"lang": "en", "value": "In Flatpak before 1.18.1, the revokefs writer, used by the flatpak-system-helper to receive repository data from unprivileged callers, validated file paths by rejecting literal .. components but did not prevent symlink traversal. A malicious local user in an active local session could obtain two revokefs sessions via the system helper, create a symlink in one session pointing into the other session's directory, and retain a file descriptor through that symlink. This allowed the attacker to modify files belonging to a different revokefs session after they had been validated and imported by the system helper. In particular, an attacker could use this to tamper with ostree commit objects in the system repository after they passed signature verification, enabling root-controlled file writes to attacker-chosen paths and local root privilege escalation."}], "metrics": [{"cvssV3_1": {"attackComplexity": "HIGH", "attackVector": "LOCAL", "availabilityImpact": "HIGH", "baseScore": 7.4, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}, "format": "CVSS", "scenarios": [{"lang": "en", "value": "GENERAL"}]}], "problemTypes": [{"descriptions": [{"cweId": "CWE-61", "description": "CWE-61 UNIX Symbolic Link (Symlink) Following", "lang": "en", "type": "CWE"}]}], "providerMetadata": {"orgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca", "shortName": "mitre", "dateUpdated": "2026-09-23T16:58:37.139Z"}, "references": [{"url": "https://github.com/flatpak/flatpak/security/advisories/GHSA-qrwq-7qwx-q9rp"}], "solutions": [{"lang": "en", "supportingMedia": [{"base64": false, "type": "text/html", "value": "<p>Fixed in 1.18.1 by commits:</p>\n<ul>\n<li><a target=\"_blank\" rel=\"noopener noreferrer\" href=\"https://github.com/flatpak/flatpak/commit/a3583bc87d4f86c2794ff879ea56fce95b0b0b5f\">a3583bc</a> \"revokefs: Avoid symlink path traversal out of basefd in simple cases\"</li>\n<li><a target=\"_blank\" rel=\"noopener noreferrer\" href=\"https://github.com/flatpak/flatpak/commit/b00c7b5073a25bdc34653642de543b5ef6fe0225\">b00c7b5</a> \"revokefs: Avoid symlink path traversal in link(), rename()\"</li>\n<li><a target=\"_blank\" rel=\"noopener noreferrer\" href=\"https://github.com/flatpak/flatpak/commit/4ddb5dc0de1bd25e52627f520a49063d94f79377\">4ddb5dc</a> \"revokefs: Avoid symlink path traversal in symlink()\"</li>\n<li><a target=\"_blank\" rel=\"noopener noreferrer\" href=\"https://github.com/flatpak/flatpak/commit/e7f96b4d1533f735ace2ea21dbf770e8d4be465a\">e7f96b4</a> \"revokefs: Avoid symlink path traversal in chmod()\"</li>\n</ul>\n<p>For LTS operating system distributions, backports of these changes are available in the flatpak-1.16.x branch.</p>"}], "value": "Fixed in 1.18.1 by commits:\n\n\n\n * a3583bc https://github.com/flatpak/flatpak/commit/a3583bc87d4f86c2794ff879ea56fce95b0b0b5f \"revokefs: Avoid symlink path traversal out of basefd in simple cases\"\n\n * b00c7b5 https://github.com/flatpak/flatpak/commit/b00c7b5073a25bdc34653642de543b5ef6fe0225 \"revokefs: Avoid symlink path traversal in link(), rename()\"\n\n * 4ddb5dc https://github.com/flatpak/flatpak/commit/4ddb5dc0de1bd25e52627f520a49063d94f79377 \"revokefs: Avoid symlink path traversal in symlink()\"\n\n * e7f96b4 https://github.com/flatpak/flatpak/commit/e7f96b4d1533f735ace2ea21dbf770e8d4be465a \"revokefs: Avoid symlink path traversal in chmod()\"\n\n\n\n\nFor LTS operating system distributions, backports of these changes are available in the flatpak-1.16.x branch."}], "x_generator": {"engine": "CVE-Request-form 0.0.1"}, "cpeApplicability": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:flatpak:flatpak:*:*:*:*:*:*:*:*", "versionEndExcluding": "1.18.1"}]}]}]}}}

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{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "platforms": ["Linux"], "product": "Flatpak", "programFiles": ["revokefs/writer.c"], "repo": "https://github.com/flatpak/flatpak", "vendor": "Flatpak", "versions": [{"lessThan": "1.18.1", "status": "affected", "version": "0", "versionType": "semver"}]}], "source": "cve@mitre.org"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "In Flatpak before 1.18.1, the revokefs writer, used by the flatpak-system-helper to receive repository data from unprivileged callers, validated file paths by rejecting literal .. components but did not prevent symlink traversal. A malicious local user in an active local session could obtain two revokefs sessions via the system helper, create a symlink in one session pointing into the other session's directory, and retain a file descriptor through that symlink. This allowed the attacker to modify files belonging to a different revokefs session after they had been validated and imported by the system helper. In particular, an attacker could use this to tamper with ostree commit objects in the system repository after they passed signature verification, enabling root-controlled file writes to attacker-chosen paths and local root privilege escalation."}], "id": "CVE-2026-96808", "lastModified": "2026-09-23T17:17:25.860", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "HIGH", "attackVector": "LOCAL", "availabilityImpact": "HIGH", "baseScore": 7.4, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 1.4, "impactScore": 5.9, "source": "cve@mitre.org", "type": "Secondary"}]}, "published": "2026-09-23T17:17:25.860", "references": [{"source": "cve@mitre.org", "url": "https://github.com/flatpak/flatpak/security/advisories/GHSA-qrwq-7qwx-q9rp"}], "sourceIdentifier": "cve@mitre.org", "vulnStatus": "Received", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-61"}], "source": "cve@mitre.org", "type": "Primary"}]}

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