CVE-2026-64846: low-severity vulnerability in NixOS nix
Nix: Arbitrary file truncation outside the sandbox with recursive-nix experimental feature
Published
E-mail alert when it lands in KEV, gets a public PoC or its score goes up.
8Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 2.8epss 0.1%
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.
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:N/I:L/A:N
Affected products
NixOS · nixRelated CVEs — NixOS nix
In the same product, most dangerous first.
CVE-2024-45593CRITICALNix affected by unsafe NAR unpackingEPSS 0.6%CVE-2024-27297MEDIUMNix Corruption of fixed-output derivationsEPSS 0.6%CVE-2024-47174MEDIUMCredential leak when credentials are used with `<nix/fetchurl.nix>`EPSS 0.3%CVE-2026-39860CRITICALNix sandbox escape: file write via symlink at FOD `.tmp` copy destinationEPSS 0.2%CVE-2024-51481LOWNix allows macOS sandbox escape via built-in buildersEPSS 0.2%CVE-2025-53819HIGHNix's privilege dropping to build user broke for macOSEPSS 0.1%