epa4all: Improper Certificate Validation
CVE-2026-54342 is a high-severity improper certificate validation vulnerability in epa4all from Med-united, with a CVSS 3.1 base score of 8.1 out of 10. It can be exploited from the same local network by an unauthenticated attacker, without any action from a user. Affected epa4all versions: < 2026-05-20. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.2% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of epa4all you run against the affected versions below, and install the vendor's latest release.
- Read the advisory on github.com for workarounds and exact fixed builds.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Med-united | epa4all | < 2026-05-20 | Not stated |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- AdjacentThe attacker must be on the same local network segment.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- NoneAvailability is not affected.
Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N. Scored by CNA (github.com).
Official 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.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Certificate Validation
The product does not validate, or incorrectly validates, a certificate.
How developers prevent this class of flaw
- Certificates should be carefully managed and checked to assure that data are encrypted with the intended owner's public key.
- If certificate pinning is being used, ensure that all relevant properties of the certificate are fully validated before the certificate is pinned, including the hostname.
More Improper Certificate Validation vulnerabilities (CWE-295)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Advisories
Patches and release notes
Other references
Other vulnerabilities in epa4all
- 9.1 Critical severity
Recent Improper Certificate Validation vulnerabilities
- 9.1 Critical severity
- 7.3 High severity
- 9.1 Critical severity
- 8.2 High severity
- 9.5 Critical severity
- 9.8 Critical severity
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