VulnerabilityReceived

CVE-2026-64846

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.

LOW 2.8EPSS 0.09%

Does this matter?

Lower severity and a low EPSS score (0.09%). Track it; it rarely justifies an emergency change on its own.

Description

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: 2.8 LOWCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:N/I:L/A:N
EPSS: 0.09% probability · 0th percentile
CISA KEV: Not listed
Weakness: CWE-61, CWE-367
Source: security-advisories@github.com

References

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.