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CVE-2026-109399

8.1, high

SWUpdate through 2026.05.1 contains an improper certificate validation vulnerability in crypto/swupdate_cms_verify_openssl.c that trusts…

NVD (opens in a new tab) CVE.org (opens in a new tab)
CVSS
8.1, high high CVSS v3.1
EPSS, next 30 days
0.2% higher than 10.4% of scored CVEs
Exploitation
No public evidence
Published
12 Oct 20265 days ago

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.

Details

Vendor
Sbabic
Product
swupdate
Weakness
CWE-295 (opens in a new tab)
Status
Deferred
Updated
16 Oct 2026
Assigner
disclosure@vulncheck.com

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

References 5

Patches and fixes 1

Other references 4

The kind is read from NVD's tags where present and from the shape of the URL otherwise, so treat it as a hint.

Beyond this page

Is CVE-2026-109399 in your network?

This page tells you how dangerous CVE-2026-109399 is out there. Whether it sits on one of your devices, only a scan of your own network can tell. That is what our systems do, every day, for the companies we protect.

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  • EXYS7950 KONDRA

    Detect it if it's exploited

    Until the patch is applied, Kondra monitors your network, events and endpoints in real time. It keeps an inventory of the software installed on every endpoint, and its anomaly detection rules flag what an attacker does once inside.

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Check your exposure

Assembled from the NVD 2.0 API, the CISA Known Exploited Vulnerabilities Catalog and FIRST EPSS. Scores are as of our last collection on 17 Oct 2026, not the live upstream state.