{"cve":"CVE-2026-59163","nvd":{"published":"2026-09-18T18:17:07.807","modified":"2026-09-24T21:25:27.050","status":"Deferred","description":"Mnemosyne is a memory layer for artificial intelligence agents. Prior to v3.10.1, the auth check in mnemosyne/core/sync_server.py parsed the JWT's header and payload using base64 decoding, then passed the token to a jwt library call with options that effectively disabled signature verification. The server accepted any well-formed token regardless of the signature, including tokens with alg: none and tokens signed with the wrong key. The fix in v3.10.1 replaces the broken decode with a from-scratch HS256 verifier using only the Python standard library. For users who cannot upgrade immediately, restrict network access to the sync server endpoint to trusted clients only. Firewall, reverse proxy with mTLS, or localhost bind with SSH tunnel are all viable. The vulnerability is not exploitable against an unreachable endpoint.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N","score":9.1},"cwes":["CWE-347"],"references":["https://github.com/mnemosyne-oss/mnemosyne/commit/a0b6b8711a1a485304971710dc3571e29ff9dbeb","https://github.com/mnemosyne-oss/mnemosyne/pull/373","https://github.com/mnemosyne-oss/mnemosyne/releases/tag/v3.10.1","https://github.com/mnemosyne-oss/mnemosyne/security/advisories/GHSA-xcw4-53cc-hv32","https://github.com/mnemosyne-oss/mnemosyne/security/advisories/GHSA-xcw4-53cc-hv32"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:55:23.253742848+00:00"},"epss":{"cve":"CVE-2026-59163","score":0.00325,"percentile":0.25568,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-xcw4-53cc-hv32","url":"https://osv.dev/vulnerability/GHSA-xcw4-53cc-hv32","summary":"Mnemosyne has JWT signature verification bypass sync server that allows authentication bypass","modified":"2026-10-01T17:55:40.405617310Z","packages":[{"ecosystem":"PyPI","name":"mnemosyne-memory","purl":"pkg:pypi/mnemosyne-memory","ranges":["<3.10.1"],"fixed":["3.10.1"]}]},{"id":"PYSEC-2026-4106","url":"https://osv.dev/vulnerability/PYSEC-2026-4106","summary":"Mnemosyne has JWT signature verification bypass sync server that allows authentication bypass","modified":"2026-10-01T17:45:11.754011494Z","packages":[{"ecosystem":"PyPI","name":"mnemosyne-memory","purl":"pkg:pypi/mnemosyne-memory","ranges":["<3.10.1"],"fixed":["3.10.1"]}]}],"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."]}