# CVE-2026-64846: nix: Nix is a package manager for Linux and other Unix systems

CVE-2026-64846 is fixed in nix on 1 platform by DEBIAN-CVE-2026-64846 (version 2.35.4+dfsg-1), released August 20, 2026. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2026-64846
- Priority: Routine
- CVSS: 2.8 (low)
- EPSS: 0.0011
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Aug 20, 2026

## 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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | nix Debian 14 | 2.35.4+dfsg-1 | [DEBIAN-CVE-2026-64846](https://patchblox.com/security/data/fix/linux/debian-cve-2026-64846.md) | Aug 20, 2026 |

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Data as of 2026-11-09T07:25:28Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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