CVE-2026-50577

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Source
https://cve.org/CVERecord?id=CVE-2026-50577
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-50577.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2026-50577
Aliases
  • GHSA-vmfm-3f7g-r9qg
Published
2026-08-18T16:52:38Z
Modified
2026-09-10T03:30:51Z
Severity
  • 7.4 (High) CVSS_V3 - CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N CVSS Calculator
Summary
ePA 3.x Integration: AES-GCM Nonce Reuse via Frozen VAU Request Counter
Details

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.

Database specific 
{
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
        "CWE-323"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/50xxx/CVE-2026-50577.json"
}
References

Affected packages

Git / github.com/fbeta-gmbh/epa3-service-opensource

Affected ranges

Type
GIT
Repo
https://github.com/fbeta-gmbh/epa3-service-opensource
Events
Introduced
0 Unknown introduced commit / All previous commits are affected
Fixed
85c4c516088c38b9cf2343f388ad67a6744e9814
Fixed
984fa75ba8ace6803bc664ce4eda890756956c83
Database specific
Show details 
{
    "extracted_events": [
        {
            "introduced": "0"
        },
        {
            "fixed": "1.3.0"
        }
    ],
    "source": [
        "AFFECTED_FIELD",
        "REFERENCES"
    ]
}

Database specific

source 
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-50577.json"