CVE-2026-64846
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.
Scoring
- Severity
- LOW
- CVSS base score
- 2.8
- CVSS vector
- CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:N/I:L/A:N
- EPSS probability
- 0.09%
- CWE
- CWE-61, CWE-367
- Published
- 2026-08-20
- Last modified
- 2026-08-20
Affected products
- NixOS nix
Weakness type
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