Upstream information

CVE-2026-39860 at MITRE

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.

Other Security Trackers

SUSE information

Overall state of this security issue: Does not affect SUSE products

This issue is currently rated as having critical severity.

CVSS v3 Scores
CVSS detail CNA (GitHub)
Base Score 9
Vector CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N
Attack Vector Local
Attack Complexity Low
Privileges Required None
User Interaction None
Scope Changed
Confidentiality Impact High
Integrity Impact High
Availability Impact None
CVSSv3 Version 3.1
SUSE Bugzilla entry: 1261895 [NEW]

No SUSE Security Announcements cross referenced.


SUSE Timeline for this CVE

CVE page created: Thu Apr 9 00:19:15 2026
CVE page last modified: Fri Apr 10 18:11:32 2026