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).
References5
Metrics
- CVSS 3.1
-
7.5
HIGH
Score source: CNA
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:N - EPSS — exploit probability
- 0% percentile: 8 · as of 13 November 2026
- CWE
- CWE-674
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.