CVE-2026-77937 — Letta through 0.16.8 Cross-Tenant Impersonation via user_id Header
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. Attacke…
Published: 2026-10-20 · CVSS: 8.6 · CVSS 4.0
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.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7