๐Ÿ” CVE Alert

CVE-2026-59163

CRITICAL 9.1

Mnemosyne has JWT signature verification bypass sync server that allows authentication bypass

CVSS Score
9.1
EPSS Score
0.0%
EPSS Percentile
0th

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.

CWE CWE-347
Vendor axdsan
Product mnemosyne
Published Sep 18, 2026
Last Updated Sep 18, 2026
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CVSS v3 Breakdown

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
None

Affected Versions

AxDSan / mnemosyne
< 3.10.1

References

NVD โ†— CVE.org โ†— EPSS Data โ†—
github.com: https://github.com/mnemosyne-oss/mnemosyne/security/advisories/GHSA-xcw4-53cc-hv32 github.com: https://github.com/mnemosyne-oss/mnemosyne/pull/373 github.com: https://github.com/mnemosyne-oss/mnemosyne/commit/a0b6b8711a1a485304971710dc3571e29ff9dbeb github.com: https://github.com/mnemosyne-oss/mnemosyne/releases/tag/v3.10.1