CVE-2026-50577
Description
ePA 3.x Integration implements the authorization workflow and writes Medical Information Objects to Germany's electronic patient record. Prior to 1.3.0, ePA 3.x Integration leaves request_counter unchanged in app/vau/VAUProtokoll.py while constructing VAU messages. The frozen client request counter causes the server side to reuse AES-GCM nonce and key combinations across responses. A network attacker who collects repeated ciphertexts can recover the XOR of plaintexts and use predictable inner HTTP headers and JSON fields to recover sensitive data, including patient health records. Repeated nonces can also enable recovery of the GHASH authentication key through the Joux forbidden attack, allowing forged AES-GCM messages and injection of malicious responses. The response-counter check also fails to maintain last_response_counter, weakening replay and ordering validation. This issue is fixed in version 1.3.0.
Predictions
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
No mitigations published for this CVE yet.
The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.
Propose a mitigation on Community Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here withsource_tier=community-verified.
References
- https://github.com/fbeta-GmbH/ePA3-Service-OpenSource/commit/85c4c516088c38b9cf2343f388ad67a6744e9814
- https://github.com/fbeta-GmbH/ePA3-Service-OpenSource/pull/10
- https://github.com/fbeta-GmbH/ePA3-Service-OpenSource/releases/tag/1.3.0
- https://github.com/fbeta-GmbH/ePA3-Service-OpenSource/security/advisories/GHSA-vmfm-3f7g-r9qg
- https://www.machinespirits.de/advisory/df27cd
CWEs
CWE-323
Community-verified mitigations for this CVE will appear above when contributors publish them.
Verify integrity in audit chain (admin only). AS-IS.