{"id":"CVE-2026-109399","aliases":[],"url":"https://o3.security/vulnerability/CVE-2026-109399","summary":"SWUpdate through 2026.05.1 contains an improper certificate validation vulnerability in crypto/swupdate_cms_verify_openssl.c that trusts untrusted X.509 certificates embedded in CMS…","details":"SWUpdate through 2026.05.1 contains an improper certificate validation vulnerability in crypto/swupdate_cms_verify_openssl.c that trusts untrusted X.509 certificates embedded in CMS SignedData for chain building. Attackers holding a signing key from a sibling intermediate under the same root can embed that intermediate in the signature to install malicious updates.","published":"2026-10-12T15:16:44.440Z","modified":"2026-10-12T15:16:44.440Z","cvss":{"score":8.1,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H"},"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[],"fix":{"url":"https://github.com/sbabic/swupdate/commit/e66c5640664a31668926a24c0c84b6b6570dc0d9","label":"sbabic/swupdate@e66c564"},"references":[{"type":"WEB","url":"https://groups.google.com/g/swupdate/c/dsoMcGFnEns"},{"type":"FIX","url":"https://github.com/sbabic/swupdate/commit/e66c5640664a31668926a24c0c84b6b6570dc0d9"},{"type":"WEB","url":"https://github.com/sbabic/swupdate/blob/2026.05.1/crypto/swupdate_cms_verify_openssl.c"},{"type":"WEB","url":"https://github.com/sbabic/swupdate"},{"type":"ADVISORY","url":"https://www.vulncheck.com/advisories/swupdate-through-2026.05.1-cms-signature-verification-bypass-via-embedded-intermediates"}],"provenance":{"sources":["OSV.dev","NVD","FIRST.org (EPSS)"],"lastVerified":"2026-10-12T15:16:44.440Z"}}