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CVE-2026-110449 NixOS CVE debrief

CVE-2026-110449 is a high-severity vulnerability affecting Nix before 2.35.3 and Lix before 2.95.4. An integer overflow and resultant out-of-bounds write occur when evaluating untrusted expressions due to mishandled list allocation. This vulnerability can lead to potential code execution and data corruption. Defenders responsible for Nix installations, especially those evaluating untrusted expressions, should assess exposure and prioritize patching. The vulnerability has a CVSS score of 7.5 and is considered HIGH severity. The CVE record was published on 2026-10-14T03:59:11.284Z and has not been modified since then.

Vendor
NixOS
Product
Nix
CVSS
HIGH 7.5
CISA KEV
Not listed in stored evidence
Original CVE published
2026-10-14
Original CVE updated
2026-10-14
Advisory published
2026-10-14
Advisory updated
2026-10-14

Who should care

Defenders responsible for Nix installations, especially those evaluating untrusted expressions, should assess exposure and prioritize patching.

Why it matters

CVE-2026-110449 is a high-severity vulnerability affecting Nix and Lix, allowing for potential code execution and data corruption through integer overflow and out-of-bounds write. Defenders should prioritize patching and restrict evaluation of untrusted expressions.

  • Potential code execution through exploitation of the integer overflow vulnerability
  • Possible data corruption or unauthorized modifications due to out-of-bounds write
  • Need for verification of affected versions and remediation efforts
  • Importance of restricting evaluation of untrusted expressions in Nix

Technical summary

The vulnerability occurs due to mishandled list allocation when evaluating untrusted expressions in Nix before 2.35.3 and Lix before 2.95.4, leading to an integer overflow and resultant out-of-bounds write. This can be exploited to execute arbitrary code or corrupt data. The vulnerability affects Nix installations that evaluate untrusted expressions, and defenders should prioritize patching vulnerable installations to prevent potential exploitation.

Defensive priority

Defenders should prioritize patching vulnerable Nix installations, especially in environments where untrusted expressions are evaluated.

Recommended defensive actions

  • Patch Nix installations to version 2.35.3 or later
  • Restrict evaluation of untrusted expressions in Nix
  • Monitor Nix installations for potential exploitation attempts

Evidence notes

The CVE Program record and NVD vulnerability detail provide official information about the vulnerability. A security advisory from the NixOS discourse forum offers additional context.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-110449 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-110449

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-110449 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-110449

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

  • CVE-2026-110449

    Unverified legacy reference

    URL: https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/110xxx/CVE-2026-110449.json

    cve_program_cvelist_v5

  • Source reference

    Unverified legacy reference

    URL: https://discourse.nixos.org/t/security-advisory-for-nix-and-lix-october-2026/80547

    Supplemental source

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.