CVE-2026-77937: high-severity vulnerability in letta-ai letta
Letta through 0.16.8 Cross-Tenant Impersonation via user_id Header
Published
E-mail alert when it lands in KEV, gets a public PoC or its score goes up.
41Vexday Risk Score
No sign of exploitation. It has a public proof of concept.
ssvc Attendcvss 8.6epss 0.5%
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.
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
Affected products
letta-ai · lettapublic PoCs found — 1
cve_referencewww.lasso.security/vulnerability-database/cve-2026-77937unverified⚠ Public resources, to assess the exposure of systems you control or are authorized to test. Test only with authorization.
Related CVEs — letta-ai letta
In the same product, most dangerous first.
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