Letta through 0.16.8 ships a compose.yaml that does not enable LETTA_SERVER_SECURE, so the password middleware is never added and all API routes are unauthenticated, and it exposes a superuser PostgreSQL port with default credentials. Remote attackers can execute arbitrary Python via POST /v1/tools/run, manage /v1/admin users, or run OS commands via COPY PROGRAM.
Attack Parameters
Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Attack Requirements
None
No additional conditions
Privileges Required
None
No privileges needed
User Interaction
None
No user interaction needed
Impact Assessment
Confidentiality
High
Complete data leak
Integrity
High
Complete data modification
Availability
High
Complete denial of service
CVSS Vector v4.0
Weakness Type (CWE)
References 4
https://github.com/letta-ai/letta/blob/1131535716e8a31c9a437f8695e25ac98f203a24…
disclosure@vulncheck.com
https://github.com/letta-ai/letta/blob/1131535716e8a31c9a437f8695e25ac98f203a24…
disclosure@vulncheck.com
https://www.lasso.security/vulnerability-database/cve-2026-77936
disclosure@vulncheck.com
https://www.vulncheck.com/advisories/letta-through-0.16.8-insecure-default-conf…
disclosure@vulncheck.com