Vulnerability · Published Oct 20, 2026 · Assigned by VulnCheck
CVE-2026-77936Letta through 0.16.8 Insecure Default Configuration Unauthenticated API and PostgreSQL Access
Critical 9.8
In plain English
A critical-severity security flaw in letta from letta-ai. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.6% (higher than 48% of all known vulnerabilities).
Severity (CVSS 3.1)9.8Critical
Exploit odds (30 days)0.6%top 51.7% of all CVEs
Exploited in the wildNo reportsCISA SSVC: poc
Attack toolingNoneno public tooling known
Official description
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.
Affected products (as reported)
Weakness: CWE-1188 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
References
- Lasso.security Advisory technical-description, exploit
- https://github.com/letta-ai/letta/blob/1131535716e8a31c9a437f8695e25ac98f203a24/compose.yaml#L17 technical-description
- https://github.com/letta-ai/letta/blob/1131535716e8a31c9a437f8695e25ac98f203a24/letta/server/rest_api/app.py#L799 technical-description
- VulnCheck Advisory: Letta through 0.16.8 Insecure Default Configuration Unauthenticated API and PostgreSQL Access third-party-advisory