{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-64846", "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "state": "PUBLISHED", "assignerShortName": "GitHub_M", "dateReserved": "2026-07-20T18:31:39.290Z", "datePublished": "2026-08-20T16:18:06.729Z", "dateUpdated": "2026-08-20T16:18:06.729Z"}, "containers": {"cna": {"title": "Nix: Arbitrary file truncation outside the sandbox with recursive-nix experimental feature", "problemTypes": [{"descriptions": [{"cweId": "CWE-61", "lang": "en", "description": "CWE-61: UNIX Symbolic Link (Symlink) Following", "type": "CWE"}]}, {"descriptions": [{"cweId": "CWE-367", "lang": "en", "description": "CWE-367: Time-of-check Time-of-use (TOCTOU) Race Condition", "type": "CWE"}]}], "metrics": [{"cvssV3_1": {"attackComplexity": "HIGH", "attackVector": "LOCAL", "availabilityImpact": "NONE", "baseScore": 2.8, "baseSeverity": "LOW", "confidentialityImpact": "NONE", "integrityImpact": "LOW", "privilegesRequired": "LOW", "scope": "CHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:N/I:L/A:N", "version": "3.1"}}], "references": [{"name": "https://github.com/NixOS/nix/security/advisories/GHSA-6h4g-g5j9-fm5f", "tags": ["x_refsource_CONFIRM"], "url": "https://github.com/NixOS/nix/security/advisories/GHSA-6h4g-g5j9-fm5f"}, {"name": "https://github.com/NixOS/nix/pull/15401", "tags": ["x_refsource_MISC"], "url": "https://github.com/NixOS/nix/pull/15401"}, {"name": "https://github.com/NixOS/nix/commit/26679828f74ee6e82a4100904e6361f993ff5390", "tags": ["x_refsource_MISC"], "url": "https://github.com/NixOS/nix/commit/26679828f74ee6e82a4100904e6361f993ff5390"}], "affected": [{"vendor": "NixOS", "product": "nix", "versions": [{"version": "< 2.35.0", "status": "affected"}]}], "providerMetadata": {"orgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "shortName": "GitHub_M", "dateUpdated": "2026-08-20T16:18:06.729Z"}, "descriptions": [{"lang": "en", "value": "Nix is a package manager for Linux and other Unix systems. Prior to 2.35.0, a malicious derivation executed with the recursive-nix experimental feature can exploit a time-of-check/time-of-use race involving final symlink handling in the LocalStore restore path. The race can cause writeFile to follow a substituted final symlink when opening a path with O_TRUNC instead of enforcing FinalSymlink::DontFollow, allowing the Nix process or nix-daemon to create or truncate an empty file outside the build sandbox with the daemon user's permissions. The primitive does not provide arbitrary-content writes and requires winning the race. This issue is fixed in version 2.35.0."}], "source": {"advisory": "GHSA-6h4g-g5j9-fm5f", "discovery": "UNKNOWN"}}}}

{}

{"affected": [{"affectedData": [{"product": "nix", "vendor": "NixOS", "versions": [{"status": "affected", "version": "< 2.35.0"}]}], "source": "[email protected]"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "Nix is a package manager for Linux and other Unix systems. Prior to 2.35.0, a malicious derivation executed with the recursive-nix experimental feature can exploit a time-of-check/time-of-use race involving final symlink handling in the LocalStore restore path. The race can cause writeFile to follow a substituted final symlink when opening a path with O_TRUNC instead of enforcing FinalSymlink::DontFollow, allowing the Nix process or nix-daemon to create or truncate an empty file outside the build sandbox with the daemon user's permissions. The primitive does not provide arbitrary-content writes and requires winning the race. This issue is fixed in version 2.35.0."}], "id": "CVE-2026-64846", "lastModified": "2026-08-20T17:19:16.813", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "HIGH", "attackVector": "LOCAL", "availabilityImpact": "NONE", "baseScore": 2.8, "baseSeverity": "LOW", "confidentialityImpact": "NONE", "integrityImpact": "LOW", "privilegesRequired": "LOW", "scope": "CHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:N/I:L/A:N", "version": "3.1"}, "exploitabilityScore": 1.1, "impactScore": 1.4, "source": "[email protected]", "type": "Secondary"}]}, "published": "2026-08-20T17:19:16.813", "references": [{"source": "[email protected]", "url": "https://github.com/NixOS/nix/commit/26679828f74ee6e82a4100904e6361f993ff5390"}, {"source": "[email protected]", "url": "https://github.com/NixOS/nix/pull/15401"}, {"source": "[email protected]", "url": "https://github.com/NixOS/nix/security/advisories/GHSA-6h4g-g5j9-fm5f"}], "sourceIdentifier": "[email protected]", "vulnStatus": "Received", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-61"}, {"lang": "en", "value": "CWE-367"}], "source": "[email protected]", "type": "Primary"}]}

{}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[0,2.35.0)"}}], "enrichment": {"confidence": 100.0, "confidence_source": "matching", "scores": [{"score": 100.0, "source": "matching"}]}, "original": {"product": "nix", "source": "cna", "vendor": "NixOS"}, "product": "nix", "vendor": "nixos"}], "created": "2026-08-20T18:00:03.693225+00:00", "updated": "2026-08-20T18:00:03.693243+00:00", "vendors": ["nixos", "nixos$PRODUCT$nix"]}