CVE-2026-59163
The vulnerability is not exploitable against an unreachable endpoint.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.25%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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 3.1
- 9.1 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
- EPSS
- 0.25% probability · 17th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-347
- Source
- security-advisories@github.com
EPSS 0.3% since 19 September 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
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
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.