Vulnerability · Published May 5, 2026 · Assigned by mitre
CVE-2026-44028
High 7.5
In plain English
A high-severity security flaw in Lix from Lix Project. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 8% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
An 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).
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:13 | nix | no fix listed | DEBIAN-CVE-2026-44028 |
| Debian:14 | nix | 2.34.8+dfsg-1 | DEBIAN-CVE-2026-44028 |
| Ubuntu:25.10 | nix | no fix listed | UBUNTU-CVE-2026-44028 |
| Ubuntu:26.04:LTS | nix | no fix listed | UBUNTU-CVE-2026-44028 |
| Ubuntu:26.10 | nix | no fix listed | UBUNTU-CVE-2026-44028 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| NixOS | Nix | 2.24.4 – before 2.28.72.29.0 – before 2.29.42.30.0 – before 2.30.52.31.0 – before 2.31.52.32.0 – before 2.32.82.33.0 – before 2.33.62.34.0 – before 2.34.7 |
| Lix Project | Lix | 2.93.0 – before 2.93.42.94.0 – before 2.94.22.95.0 – before 2.95.2 |
Weakness: CWE-674 · Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:N
References
- 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
- https://www.openwall.com/lists/oss-security/2026/05/04/32
- https://lix.systems/blog/2026-05-05-lix-unsigned-integer-overflow/