CVE-2026-109399

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.

CVSS v3 8.1 HIGH

8.1^/10

CVSS v3 : HIGH

Vector :

Exploitability : 2.2 / Impact : 5.9

Attack Vector NETWORK

Attack Complexity HIGH

Privileges Required NONE

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact HIGH

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
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

Configurations

No configuration.

History

12 Oct 2026, 16:17

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-10-12 16:17

Updated : 2026-10-18 12:17

NVD link : CVE-2026-109399

Mitre link : CVE-2026-109399

CVE.ORG link : CVE-2026-109399

JSON object : View

Products Affected

No product.

CWE

CWE-295

Improper Certificate Validation

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