2.8

CVE-2026-64846

Nix: Arbitrary file truncation outside the sandbox with recursive-nix experimental feature

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.
Daten sind bereitgestellt durch das CVE Programm von einer CVE Numbering Authority (CNA) (Unstrukturiert).
HerstellerNixOS
≫
Produkt nix
Version < 2.35.0
Status affected
VulnDex Vulnerability Enrichment
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CVSS Metriken
Quelle Base Score Exploit Score Impact Score Vector String
security-advisories@github.com 2.8 1.1 1.4
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:N/I:L/A:N
CWE-367 Time-of-check Time-of-use (TOCTOU) Race Condition

The product checks the state of a resource before using that resource, but the resource's state can change between the check and the use in a way that invalidates the results of the check.

CWE-61 UNIX Symbolic Link (Symlink) Following

The product, when opening a file or directory, does not sufficiently account for when the file is a symbolic link that resolves to a target outside of the intended control sphere. This could allow an attacker to cause the product to operate on unauthorized files.

https://github.com/NixOS/nix/security/advisories/GHSA-6h4g-g5j9-fm5f
https://github.com/NixOS/nix/pull/15401
https://github.com/NixOS/nix/commit/26679828f74ee6e82a4100904e6361f993ff5390