CVE-2026-39860
9.0 · CRITICALOverview
CVE-2026-39860 is a critical-severity vulnerability affecting nixos nix. It was published on April 8, 2026 and has a CVSS 3.1 base score of 9.0 (CRITICAL).
This vulnerability has a CVSS 3.1 base score of 9.0, rated CRITICAL. It requires local or adjacent network access to exploit. No authentication or special privileges are required for exploitation.
Technical 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
Remediation
Check the references section for vendor advisories and patches from nixos. Update nix to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
Affected Products
| Vendor | Product | Versions | Status |
|---|---|---|---|
| nixos | nix | 2.18.2 | Affected |
References
Frequently Asked Questions
What is CVE-2026-39860?
CVE-2026-39860 is a critical-severity vulnerability affecting nixos nix. It was published on April 8, 2026 and has a CVSS 3.1 base score of 9.0 (CRITICAL).
How severe is CVE-2026-39860?
This vulnerability has a CVSS 3.1 base score of 9.0, rated CRITICAL. It requires local or adjacent network access to exploit. No authentication or special privileges are required for exploitation.
How do I fix or remediate CVE-2026-39860?
Check the references section for vendor advisories and patches from nixos. Update nix to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2026-39860?
CyberStrike's AI-powered security agents can automatically detect CVE-2026-39860 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.
How CyberStrike Helps
AI agents map your attack surface to find vulnerabilities like this one.
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