CVE-2026-77936
Letta through 0.16.8 Insecure Default Configuration Unauthenticated API and PostgreSQL Access
letta-ai letta
CVSS
9.3CriticalExploitationPublic exploit codeCISA's assessment says proof of concept code is public, assessed 20 Oct 2026. Not in the KEV catalogCISA via CVE List
Exploit odds (EPSS)0.47%Chance of exploitation activity in the next 30 days, higher than 39% of CVEs. Scored 23 Oct 2026FIRST EPSS
Fixed inNone listedNo source names a fixed version. Check the vendor advisory below
What fixes it
No source in this snapshot names a fixed version. The vendor advisories under References are the place to check.
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.
Text from CVE List
Affected versions 1
- lettaaffected: all versions through 0.16.8CVE List
References 4
- vulncheck.com/advisories/letta-through-0.16.8-insecure-default-configuration-unauthenticated-api-and-postgresql-accessAdvisoryvia CVE List
- lasso.security/vulnerability-database/cve-2026-77936Exploitvia CVE List
- github.com/letta-ai/letta/blob/1131535716e8a31c9a437f8695e25ac98f203a24/compose.yaml#L17Referencevia CVE List
- github.com/letta-ai/letta/blob/1131535716e8a31c9a437f8695e25ac98f203a24/letta/server/rest_api/app.py#L799Referencevia CVE List