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CVE-2026-64846

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

Description (CNA)

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.

Affected (CNA)

Vendor / productVersions
NixOS / nixaffected < 2.35.0

CWE

CWE-61, CWE-367

References

ADP enrichment

CISA-ADP

No English description supplied.

No references supplied.