CVE-2026-109399
HIGHCVSS 8.1Description
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.
Timeline
Published:October 12th, 2026 4:17 PM
Last modified:October 18th, 2026 12:17 PM
CVSS Scoring
CVSS v3: 8.1 (HIGH)
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Weaknesses (CWE)
References & Reports
Advisories, patches, and third-party reports
- https://github.com/sbabic/swupdate
- https://github.com/sbabic/swupdate/blob/2026.05.1/crypto/swupdate_cms_verify_openssl.c
- https://github.com/sbabic/swupdate/commit/e66c5640664a31668926a24c0c84b6b6570dc0d9
- https://groups.google.com/g/swupdate/c/dsoMcGFnEns
- https://www.vulncheck.com/advisories/swupdate-through-2026.05.1-cms-signature-verification-bypass-via-embedded-intermediates
Source: NIST NVD · Data may lag official sources by up to one minute