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National Vulnerability Database

National Vulnerability Database

NVD

National Vulnerability Database
  1. Vulnerabilities

CVE-2026-39860 Detail

Description

Nix is a package manager for Linux and other Unix systems. A bug in the fix for CVE-2024-27297 allowed for arbitrary overwrites of files writable by the Nix process orchestrating the builds (typically the Nix daemon running as root in multi-user installations) by following symlinks during fixed-output derivation output registration. This affects sandboxed Linux builds - sandboxed macOS builds are unaffected. The location of the temporary output used for the output copy was located inside the build chroot. A symlink, pointing to an arbitrary location in the filesystem, could be created by the derivation builder at that path. During output registration, the Nix process (running in the host mount namespace) would follow that symlink and overwrite the destination with the derivation's output contents. In multi-user installations, this allows all users able to submit builds to the Nix daemon (allowed-users - defaulting to all users) to gain root privileges by modifying sensitive files. This vulnerability is fixed in 2.34.5, 2.33.4, 2.32.7, 2.31.4, 2.30.4, 2.29.3, and 2.28.6.


Metrics

 
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CVSS 4.0 Severity and Vector Strings:

NIST CVSS score
NIST: NVD
N/A
NVD assessment not yet provided.

References to Advisories, Solutions, and Tools

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URL Source(s) Tag(s)
https://github.com/NixOS/nix/commit/244f3eee0bbc7f11e9b383a15ed7368e2c4becc9 GitHub, Inc. Patch 
https://github.com/NixOS/nix/commit/4bc5a3510fa3735798f9ed3a2a30a3ea7b32343a GitHub, Inc. Patch 
https://github.com/NixOS/nix/commit/7794354a982449927ee7401cdeb573ddd16c4688 GitHub, Inc. Patch 
https://github.com/NixOS/nix/commit/a3163b9eabb952b4aa96e376dea95ebcca97b31a GitHub, Inc. Patch 
https://github.com/NixOS/nix/pull/10178 GitHub, Inc. Issue Tracking  Patch 
https://github.com/NixOS/nix/security/advisories/GHSA-g3g9-5vj6-r3gj GitHub, Inc. Mitigation  Patch  Vendor Advisory 

Weakness Enumeration

CWE-ID CWE Name Source
CWE-61 UNIX Symbolic Link (Symlink) Following GitHub, Inc.  

Known Affected Software Configurations Switch to CPE 2.2

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Change History

2 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2026-39860
NVD Published Date:
04/08/2026
NVD Last Modified:
04/15/2026
Source:
GitHub, Inc.