HIGH 8.6 NVD
CVE-2026-77937
Letta through 0.16.8 contains an authentication bypass vulnerability that allows API callers to impersonate other users by supplying a self-asserted user_id HTT
Letta through 0.16.8 contains an authentication bypass vulnerability that allows API callers to impersonate other users by supplying a self-asserted user_id HTTP header. Attackers can set user_id to another tenant's ID, even with LETTA_SERVER_SECURE enabled, to read and modify that user's agents, memory and configuration.
References
- https://github.com/letta-ai/letta/blob/1131535716e8a31c9a437f8695e25ac98f203a24/letta/serv
- https://www.lasso.security/vulnerability-database/cve-2026-77937
- https://www.vulncheck.com/advisories/letta-through-0.16.8-cross-tenant-impersonation-via-u
This high severity vulnerability with a CVSS score of 8.6 was published on 2026-10-20 via NVD.
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