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CVE-2026-109399

SWUpdate vulnerability

8.1 HIGH
  1. Published12 Oct 2026

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.

CVSS 3.1 breakdown

Attack vectorNetwork
Attack complexityHigh
Privileges requiredNone
User interactionNone
ScopeUnchanged
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

Remediation

No fixed version is recorded in the NVD data. Check the vendor advisory for the latest guidance.

References

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Frequently asked

Is CVE-2026-109399 being actively exploited?

CVE-2026-109399 is not in the CISA KEV catalog.

How severe is CVE-2026-109399?

CVE-2026-109399 has a CVSS 3.1 base score of 8.1, rated high.

How do I fix CVE-2026-109399?

Apply the vendor's patch or advisory guidance, then verify no affected versions remain across your devices.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2026-109399 against the real software inventory on every managed device, as each hourly inventory arrives. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.