CVE-2026-54342: Cert Validation Flaw (CVSS 8.1)

Description

In epa4all, prior to version 2026-05-20, an attacker on the network path between epa4all and any backend (ePA Aktensystem, Konnektor, IDP, TSS) can present a self-signed TLS certificate and intercept the connection. For non-VAU connections (Konnektor, IDP), this allows direct read and modification of the inner traffic, including smartcard operations and OIDC authentication exchanges. For the ePA backend, the disabled TLS verification is the transport-level enabler for the VAU MITM described in GHSA-vvh7-x6c7-46gh. This issue has been patched in version 2026-05-20.

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CVSS v3.1 Score

8.1

HIGH

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

EPSS — Exploit Prediction

0.0013

Probability of exploitation

0.03%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-295 CWE-295

References

Other References

https://github.com/med-united/epa4all/releases/tag/2026-05-20 https://github.com/med-united/epa4all/security/advisories/GHSA-296w-v8f6-3rf7 https://github.com/med-united/epa4all/security/advisories/GHSA-vvh7-x6c7-46gh https://www.machinespirits.com/advisory/b98b02

Frequently Asked Questions

What is CVE-2026-54342? +

In epa4all, prior to version 2026-05-20, an attacker on the network path between epa4all and any backend (ePA Aktensystem, Konnektor, IDP, TSS) can present a self-signed TLS certificate and intercept the connection. For non-VAU connections (Konnektor, IDP), this allows direct read and modification of the inner traffic, including smartcard operations and OIDC authentication exchanges. For the ePA backend, the disabled TLS verification is the transport-level enabler for the VAU MITM described in GHSA-vvh7-x6c7-46gh. This issue has been patched in version 2026-05-20. It has a CVSS v3.1 base score of 8.1 (HIGH).

How severe is CVE-2026-54342? +

CVE-2026-54342 has a CVSS v3.1 score of 8.1 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0013, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-54342? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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