{"id":"CVE-2026-109399","published":"2026-10-12T16:17:05.557","lastModified":"2026-10-16T19:18:44.867","description":"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.","cvssScore":8.1,"cvssSeverity":"HIGH","cvssVector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H","cwes":["CWE-295"],"vendors":[],"products":[],"references":[{"url":"https://github.com/sbabic/swupdate","tags":[]},{"url":"https://github.com/sbabic/swupdate/blob/2026.05.1/crypto/swupdate_cms_verify_openssl.c","tags":[]},{"url":"https://github.com/sbabic/swupdate/commit/e66c5640664a31668926a24c0c84b6b6570dc0d9","tags":[]},{"url":"https://groups.google.com/g/swupdate/c/dsoMcGFnEns","tags":[]},{"url":"https://www.vulncheck.com/advisories/swupdate-through-2026.05.1-cms-signature-verification-bypass-via-embedded-intermediates","tags":[]}],"exploitRefs":[{"url":"https://github.com/sbabic/swupdate","tags":[]},{"url":"https://github.com/sbabic/swupdate/blob/2026.05.1/crypto/swupdate_cms_verify_openssl.c","tags":[]},{"url":"https://github.com/sbabic/swupdate/commit/e66c5640664a31668926a24c0c84b6b6570dc0d9","tags":[]}],"hasPoc":true,"ai":null}