CVE-2026-77936 Letta - Authentication Bypass & Remote Code Execution

Letta <= 0.16.8 contains an authentication bypass caused by missing LETTA_SERVER_SECURE setting and default PostgreSQL credentials, letting remote attackers execute arbitrary Python, manage users, and run OS commands via API endpoints, exploit requires network access.

CVSS base score 9.8 /10
Critical
CISA KEV
Not listed
Public exploit
None known
Authentication
Not required
View the NVD record ↗

Details

Type
Authentication Bypass
Impact
Remote Code Execution, Broken Access Control
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Published
20 October 2026
Updated
20 October 2026
Weakness
CWE-1188

Vendor fix

Update to a version later than 0.16.8 with LETTA_SERVER_SECURE enabled and secure PostgreSQL credentials.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

References

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