Insecure Default Configuration in Letta API Exposes User Data and PostgreSQL Access
CVE-2026-77936

9.3CRITICAL

Key Information:

Vendor

Letta-ai

Status
Letta
Vendor
CVE Published:
20 October 2026

Badges

👾 Exploit Exists🟡 Public PoC

What is CVE-2026-77936?

The Letta application, up to version 0.16.8, features a configuration flaw that results in a lack of secure server settings, leading to severe security implications. Specifically, the default settings in the compose.yaml file do not activate the LETTA_SERVER_SECURE option, resulting in all API routes being left unauthenticated. This oversight allows remote attackers to exploit the system by executing arbitrary Python code through a vulnerable API endpoint /v1/tools/run, managing administrative user accounts via the /v1/admin route, and potentially running operating system commands through PostgreSQL with default credentials on an exposed superuser port. Users should immediately address this vulnerability to protect their systems from unauthorized access and command execution.

Affected Version(s)

letta 0 <= 0.16.8

Exploit Proof of Concept (PoC)

PoC code is written by security researchers to demonstrate the vulnerability can be exploited. PoC code is also a key component for weaponization which could lead to ransomware.

CVE-2026-77936 - Proof of Concept

References

https://www.lasso.security/vulnerability-database/cve-202...
technical-descriptionexploit
https://github.com/letta-ai/letta/blob/1131535716e8a31c9a...
technical-description
https://github.com/letta-ai/letta/blob/1131535716e8a31c9a...
technical-description

CVSS V4

Score:
9.3
Severity:
CRITICAL
Confidentiality:
High
Integrity:
High
Availability:
High
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • 🟡

    Public PoC available

  • 👾

    Exploit known to exist

  • Vulnerability published

  • Vulnerability Reserved

Credit

Noy Pearl
Michael Sromin
Ophir Dror
.