{"cve":"CVE-2026-50577","nvd":{"published":"2026-08-18T17:16:58.790","modified":"2026-10-22T22:10:00.250","status":"Deferred","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.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N","score":7.4},"cwes":["CWE-323"],"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"],"products":[],"source":"nvd","synced_at":"2026-10-23T16:39:26.291718493+00:00"},"epss":{"cve":"CVE-2026-50577","score":0.00513,"percentile":0.43476,"date":"2026-10-25"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}