CVE-2026-44028

NameCVE-2026-44028
DescriptionAn issue was discovered in Nix before 2.34.7 and Lix before 2.95.2. Unbounded recursion in the NAR (Nix Archive) parser could lead to a stack-to-heap overflow when the parser is run on a coroutine stack. The stack is allocated without a guard page, which means that a stack overflow could overwrite memory on the heap and could allow arbitrary code execution as the Nix daemon (run as root in multi-user installations) if ASLR hardening is bypassed. This can be exploited by all users able to connect to the daemon (e.g., in Nix, this is configurable via the allowed-users setting, defaulting to all users). The fixed versions are 2.34.7, 2.33.6, 2.32.8, 2.31.5, 2.30.5, 2.29.4, and 2.28.7 for Nix (introduced in 2.24.4); and 2.95.2, 2.94.2, and 2.93.4 for Lix (introduced in 2.93.0).
SourceCVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
nix (PTS)bullseye2.3.7+dfsg1-1vulnerable
bookworm2.8.0-1.1fixed
trixie2.26.3+dfsg-1vulnerable
forky, sid2.34.6+dfsg-1vulnerable

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
nixsourcebookworm(not affected)
nixsource(unstable)(unfixed)

Notes

[bookworm] - nix <not-affected> (Vulnerable code introduced later)
https://discourse.nixos.org/t/security-advisory-local-privilege-escalation-in-lix-and-nix/77407
https://github.com/NixOS/nix/security/advisories/GHSA-vh5x-56v6-4368
https://www.openwall.com/lists/oss-security/2026/05/04/33

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