Track vulnerabilities like this one. Sign up free to get alerted when software you use is affected.
9.1

Mnemosyne sync server lets any token log in

CVE-2026-59163 · published 21 days ago
Summary

The Mnemosyne memory service’s sync server could accept any login token, even if it was not properly signed, allowing unauthorized users to appear authenticated. Updating to version 3.10.1 fixes the check, and until you can upgrade you should limit network access to the sync server – for example by using a firewall, a reverse proxy with client‑certificate checks, or binding the service to localhost and tunneling with SSH. This protects the system as long as the server is not publicly reachable.

What to do
  • Update mnemosyne-memory to version 3.10.1.
  • Update abdias j mnemosyne-memory to version 3.10.1.
Affected software
Ecosystem VendorProductAffected versions
– axdsan mnemosyne < 3.10.1
pip – mnemosyne-memory <= 3.10.0
Fix: upgrade to 3.10.1
PyPI – mnemosyne-memory < 3.10.1
Fix: upgrade to 3.10.1
pip abdias j mnemosyne-memory <= 3.10.0
Fix: upgrade to 3.10.1
Original advisory text
Mnemosyne has JWT signature verification bypass sync server that allows authentication bypass
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.
References
Fix within
Internet-facing 3 days
Internal 60 days
  • Not known to be exploited
  • Can be exploited automatically
  • Gives an attacker full control
Severity
9.1 Critical
Exploitation
<1% chance of attack within 30 days
Type
CWE-347Improper Verification of Cryptographic Signature
Timeline
Published18 Sep 2026
Updated9 Oct 2026
First seen18 Sep 2026
Sources
CVE-2026-59163 · NVD
CVE-2026-59163 · MITRE
GHSA-xcw4-53cc-hv32 · GHSA
CVE-2026-59163 · OSV
GHSA-xcw4-53cc-hv32 · OSV
PYSEC-2026-4106 · OSV
Track software like this
Free during beta