{"id":"CVE-2026-109399","revision":"ca2aae93e6224e9cb90ff50cbe10ca34","records":[{"revision":"ca2aae93e6224e9cb90ff50cbe10ca34","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-109399","aliases":[],"title":"SWUpdate through 2026.05.1 CMS Signature Verification Bypass via Embedded Intermediates","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.","state":0,"publishedAt":"2026-10-12T15:16:44.44+00:00","modifiedAt":"2026-10-18T12:03:15.694+00:00","affected":[{"ecosystem":"Vendor product","name":"swupdate","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"vendor\": \"sbabic\",\n                    \"product\": \"swupdate\",\n                    \"defaultStatus\": \"unaffected\",\n                    \"versions\": [\n                        {\n                            \"version\": \"0\",\n                            \"lessThanOrEqual\": \"2026.05.1\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"custom\"\n                        }\n                    ],\n                    \"packageURL\": \"pkg:github/sbabic/swupdate\",\n                    \"repo\": \"https://github.com/sbabic/swupdate\"\n                }"}],"metrics":[{"system":"CVSS 4.0","vector":"CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N","score":9.2,"severity":"CRITICAL"},{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H","score":8.1,"severity":"HIGH"}],"references":["https://groups.google.com/g/swupdate/c/dsoMcGFnEns","https://github.com/sbabic/swupdate/commit/e66c5640664a31668926a24c0c84b6b6570dc0d9","https://github.com/sbabic/swupdate/blob/2026.05.1/crypto/swupdate_cms_verify_openssl.c","https://github.com/sbabic/swupdate","https://www.vulncheck.com/advisories/swupdate-through-2026.05.1-cms-signature-verification-bypass-via-embedded-intermediates"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-109399","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-109399","identifiers":["CVE-2026-109399"]},"retained":false,"historicalAffected":[]}],"coverage":[]}