{"id":"UBUNTU-CVE-2026-44028","details":"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).","modified":"2026-05-20T16:26:03.725396065Z","published":"2026-05-05T01:16:00Z","upstream":["CVE-2026-44028"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-44028"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-44028"},{"type":"REPORT","url":"https://discourse.nixos.org/t/security-advisory-local-privilege-escalation-in-lix-and-nix/77407"},{"type":"REPORT","url":"https://github.com/NixOS/nix/security/advisories/GHSA-vh5x-56v6-4368"},{"type":"REPORT","url":"https://www.openwall.com/lists/oss-security/2026/05/04/33"}],"affected":[{"package":{"name":"nix","ecosystem":"Ubuntu:Pro:22.04:LTS","purl":"pkg:deb/ubuntu/nix?arch=source&distro=esm-apps%2Fjammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.3.10+dfsg1-1","2.3.10+dfsg1-1build1","2.6.0+dfsg-2","2.6.0+dfsg-3","2.6.0+dfsg-3ubuntu0.1~esm1"],"ecosystem_specific":{"binaries":[{"binary_name":"nix-bin","binary_version":"2.6.0+dfsg-3ubuntu0.1~esm1"},{"binary_name":"nix-setup-systemd","binary_version":"2.6.0+dfsg-3ubuntu0.1~esm1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-44028.json"}},{"package":{"name":"nix","ecosystem":"Ubuntu:Pro:24.04:LTS","purl":"pkg:deb/ubuntu/nix?arch=source&distro=esm-apps%2Fnoble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.16.1+dfsg-3ubuntu1","2.18.1+dfsg-1ubuntu1","2.18.1+dfsg-1ubuntu2","2.18.1+dfsg-1ubuntu4","2.18.1+dfsg-1ubuntu5","2.18.1+dfsg-1ubuntu5+esm2"],"ecosystem_specific":{"binaries":[{"binary_name":"nix-bin","binary_version":"2.18.1+dfsg-1ubuntu5+esm2"},{"binary_version":"2.18.1+dfsg-1ubuntu5+esm2","binary_name":"nix-setup-systemd"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-44028.json"}},{"package":{"name":"nix","ecosystem":"Ubuntu:25.10","purl":"pkg:deb/ubuntu/nix?arch=source&distro=questing"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.24.9+dfsg-2ubuntu2","2.26.3+dfsg-1ubuntu1","2.26.3+dfsg-1ubuntu2","2.26.3+dfsg-1ubuntu4"],"ecosystem_specific":{"binaries":[{"binary_name":"nix-bin","binary_version":"2.26.3+dfsg-1ubuntu4"},{"binary_name":"nix-setup-systemd","binary_version":"2.26.3+dfsg-1ubuntu4"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-44028.json"}},{"package":{"name":"nix","ecosystem":"Ubuntu:26.04:LTS","purl":"pkg:deb/ubuntu/nix?arch=source&distro=resolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.26.3+dfsg-1ubuntu4","2.26.3+dfsg-1ubuntu5","2.32.5+dfsg-1ubuntu3","2.32.5+dfsg-2ubuntu1","2.34.3+dfsg-1"],"ecosystem_specific":{"binaries":[{"binary_name":"nix-bin","binary_version":"2.34.3+dfsg-1"},{"binary_name":"nix-setup-systemd","binary_version":"2.34.3+dfsg-1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-44028.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:N"},{"type":"Ubuntu","score":"medium"}]}