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Vulnerabilities

Vulnerability · CVE-2026-39860

Nix is a package manager for Linux and other Unix systems.

Published Apr 8, 2026 · catalog updated Jul 24, 2026 · Nix is a package

Check if you run it

No confirmed exploitation is on record for CVE-2026-39860. EPSS is 0.18%. Act only if a listed version of Nix is a package is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (Nix is a package).
  • No version range is stored. A customer cannot check an installed version against this record.
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
High8.4
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.18%
Remediation
Advisory link
Affected products
cpe nixos/nix

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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe nixos/nixversion unspecified

How to fix CVE-2026-39860

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-39860. EPSS is 0.18%. Act only if a listed version of Nix is a package is installed.

Which versions are affected?

Affected version ranges are not on this record. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-61. EPSS 0.18%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Apr 8, 2026 · NIST NVD

    Detected

    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

  2. Jul 24, 2026 · NIST NVD

    Updated

    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

Sources

  • CVE.orgVulnerability recordCVE-2026-39860

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-39860

    30-day exploitation probability 0.2%

    first.org
  • NIST NVDVulnerability recordCVE-2026-39860

    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 symlin

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.