Vulnary
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Critical· 9official fix available

CVE-2026-39860

A flaw in the Nix package manager allows a user to overwrite sensitive files on a system by using symbolic links during the build process. This occurs because the Nix process follows these links to locations outside the intended build area.

publishedApr 8, 2026
last modifiedJul 24, 2026
sourcesNVD
severity · cvss
9
critical · how bad it is
exploitation · epss
<1%
9th percentile · chance of exploitation in 30 days
(ai-assisted) A model wrote this summary from the official data, so double-check it against the source before you act on it. Read the official advisory →
auto-deletes from the system
counting…on Aug 25, 2026

An official fix is available, so this entry is kept for 30 days and then removed automatically.

01

Who is affected

Users of the Nix package manager on Linux systems, specifically in multi-user installations where the Nix daemon runs with root privileges.

02

Real-world impact

An attacker with permission to submit builds to the Nix daemon could gain full root privileges by overwriting critical system files.

03

Why this severity

The critical score is due to the fact that an attacker can achieve full system compromise (root access) with low complexity and no user interaction required.

04

What to do about it

official fix available
recommended steps
  1. 01Upgrade Nix to version 2.34.5, 2.33.4, 2.32.7, 2.31.4, 2.30.4, 2.29.3, or 2.28.6 or later.

NVD-referenced vendor advisory

05

Timeline

  1. Apr 8, 2026 · Apr 8, 2026
    Published
    Disclosed and added to the National Vulnerability Database.
  2. Jul 24, 2026 · 11d ago
    Advisory updated
    The NVD record was last revised.
  3. Jul 26, 2026 · 10d ago
    Official fix available
    A vendor patch or mitigation now exists — see the remediation steps above.
06

How it’s attacked

Attack vectorLocal
Attack complexityLow
Privileges requiredNone
User interactionNone needed
ScopeChanged
Confidentiality impactHigh
Integrity impactHigh
Availability impactNone
07

References & advisories

NVD advisory ↗Search advisories ↗
(ai-assisted) A model wrote this summary from the official data, so double-check it against the source before you act on it. Read the official advisory →
CVE-2026-39860: A flaw in the Nix package manager allows a user to overwrite sensitive · Vulnary