{"id":"CVE-2026-44028","state":"PUBLISHED","title":"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 ru","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).","publishedAt":"2026-05-05T00:30:16.205Z","updatedAt":"2026-05-09T03:40:06.637Z","severity":{"score":7.5,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:N","source":"mitre"},"assigner":"mitre","products":["NixOS Nix","Lix Project Lix"],"affected":[{"vendor":"NixOS","product":"Nix","defaultStatus":"unaffected","versions":[{"version":"2.24.4","status":"affected","lessThan":"2.28.7","versionType":"semver"},{"version":"2.29.0","status":"affected","lessThan":"2.29.4","versionType":"semver"},{"version":"2.30.0","status":"affected","lessThan":"2.30.5","versionType":"semver"},{"version":"2.31.0","status":"affected","lessThan":"2.31.5","versionType":"semver"},{"version":"2.32.0","status":"affected","lessThan":"2.32.8","versionType":"semver"},{"version":"2.33.0","status":"affected","lessThan":"2.33.6","versionType":"semver"},{"version":"2.34.0","status":"affected","lessThan":"2.34.7","versionType":"semver"}]},{"vendor":"Lix Project","product":"Lix","defaultStatus":"unaffected","versions":[{"version":"2.93.0","status":"affected","lessThan":"2.93.4","versionType":"semver"},{"version":"2.94.0","status":"affected","lessThan":"2.94.2","versionType":"semver"},{"version":"2.95.0","status":"affected","lessThan":"2.95.2","versionType":"semver"}]}],"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/"],"weaknesses":["CWE-674"],"ingestedAt":"2026-10-29T20:11:57.932Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/44xxx/CVE-2026-44028.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-44028","state":"PUBLISHED","datePublished":"2026-05-05T00:30:16.205Z","dateUpdated":"2026-05-09T03:40:06.637Z","assignerShortName":"mitre","assignerOrgId":"8254265b-2729-46b6-b9e3-3dfca2d5bfca","dateReserved":"2026-05-05T00:29:44.087Z"},"containers":{"cna":{"descriptions":[{"lang":"en","value":"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":[{"vendor":"NixOS","product":"Nix","defaultStatus":"unaffected","versions":[{"version":"2.24.4","status":"affected","lessThan":"2.28.7","versionType":"semver"},{"version":"2.29.0","status":"affected","lessThan":"2.29.4","versionType":"semver"},{"version":"2.30.0","status":"affected","lessThan":"2.30.5","versionType":"semver"},{"version":"2.31.0","status":"affected","lessThan":"2.31.5","versionType":"semver"},{"version":"2.32.0","status":"affected","lessThan":"2.32.8","versionType":"semver"},{"version":"2.33.0","status":"affected","lessThan":"2.33.6","versionType":"semver"},{"version":"2.34.0","status":"affected","lessThan":"2.34.7","versionType":"semver"}]},{"vendor":"Lix Project","product":"Lix","defaultStatus":"unaffected","versions":[{"version":"2.93.0","status":"affected","lessThan":"2.93.4","versionType":"semver"},{"version":"2.94.0","status":"affected","lessThan":"2.94.2","versionType":"semver"},{"version":"2.95.0","status":"affected","lessThan":"2.95.2","versionType":"semver"}]}],"references":[{"url":"https://discourse.nixos.org/t/security-advisory-local-privilege-escalation-in-lix-and-nix/77407"},{"url":"https://github.com/NixOS/nix/security/advisories/GHSA-vh5x-56v6-4368"},{"url":"https://www.openwall.com/lists/oss-security/2026/05/04/33"},{"url":"https://www.openwall.com/lists/oss-security/2026/05/04/32"},{"url":"https://lix.systems/blog/2026-05-05-lix-unsigned-integer-overflow/"}],"metrics":[{"cvssV3_1":{"attackComplexity":"HIGH","attackVector":"LOCAL","availabilityImpact":"NONE","baseScore":7.5,"baseSeverity":"HIGH","confidentialityImpact":"HIGH","integrityImpact":"HIGH","privilegesRequired":"LOW","scope":"CHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:N","version":"3.1"},"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}]}],"problemTypes":[{"descriptions":[{"cweId":"CWE-674","description":"CWE-674 Uncontrolled Recursion","lang":"en","type":"CWE"}]}],"providerMetadata":{"shortName":"mitre","orgId":"8254265b-2729-46b6-b9e3-3dfca2d5bfca","dateUpdated":"2026-05-09T03:40:06.637Z"},"x_generator":{"engine":"CVE-Request-form 0.0.1"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-05-05T14:03:11.111278Z","id":"CVE-2026-44028","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-05-05T14:13:37.898Z"}}]}}}