What is CVE-2024-27297?

CVE-2024-27297 is a medium-severity vulnerability in Nixos Nix, classified under Time-of-check Time-of-use (TOCTOU) Race Condition. CVSS score: 6.3/10. Published 2024-03-11.

How severe is CVE-2024-27297?

Medium severity. CVSS v3 base score is 6.3 out of 10.

Is CVE-2024-27297 known to be exploited?

2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

Vulnerability in Nixos Nix

CVE-2024-27297

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.

Vulnerability class: TOCTOU (Time-of-Check to Time-of-Use)

Published 2024-03-11 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 6.3 (Medium). Vector: CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:L.

EPSS exploit prediction

EPSS: 0.006 (47.0th percentile), scored 2026-10-20.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 47th percentile — 47.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.006 · newest: 0.006 · change: 0.000

Affected products

Nixos Nix — versions >= 2.3.0, < 2.3.18, >= 2.4.0, < 2.18.2, >= 2.19.0, < 2.19.4

Weakness classification (CWE)

CWE-367 — Time-of-check Time-of-use (TOCTOU) Race Condition

Public proof-of-concept exploits

References

github.com/NixOS/nix/security/advisories/GHSA-2ffj-w4mj-pg37 (Vendor Advisory)
github.com/NixOS/nix/commit/f8170ce9f119e5e6724eb81ff1b5a2d4c0024000 (Patch)
hackmd.io/03UGerewRcy3db44JQoWvw (Exploit)
af854a3a-2127-422b-91ae-364da2661108

Frequently asked questions

What is CVE-2024-27297?: CVE-2024-27297 is a medium-severity vulnerability in Nixos Nix, classified under Time-of-check Time-of-use (TOCTOU) Race Condition. CVSS score: 6.3/10. Published 2024-03-11.
How severe is CVE-2024-27297?: Medium severity. CVSS v3 base score is 6.3 out of 10.
Is CVE-2024-27297 known to be exploited?: 2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.