---
title: "CVE-2026-77936: Letta - Authentication Bypass & Remote Code Execution"
description: "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."
url: https://panop.io/threat-heartbeat/CVE-2026-77936/
---

# 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 ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-77936)

## 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](https://cwe.mitre.org/data/definitions/1188.html)

## 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

- [https://nvd.nist.gov/vuln/detail/CVE-2026-77936](https://nvd.nist.gov/vuln/detail/CVE-2026-77936)
- [https://github.com/letta-ai/letta/blob/1131535716e8a31c9a437f8695e25ac98f203a24/compose.yaml#L17](https://github.com/letta-ai/letta/blob/1131535716e8a31c9a437f8695e25ac98f203a24/compose.yaml#L17)
- [https://github.com/letta-ai/letta/blob/1131535716e8a31c9a437f8695e25ac98f203a24/letta/server/rest\_api/app.py#L799](https://github.com/letta-ai/letta/blob/1131535716e8a31c9a437f8695e25ac98f203a24/letta/server/rest_api/app.py#L799)
- [https://www.lasso.security/vulnerability-database/cve-2026-77936](https://www.lasso.security/vulnerability-database/cve-2026-77936)
- [https://www.vulncheck.com/advisories/letta-through-0.16.8-insecure-default-configuration-unauthenticated-api-and-postgresql-access](https://www.vulncheck.com/advisories/letta-through-0.16.8-insecure-default-configuration-unauthenticated-api-and-postgresql-access)

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## What this record can't tell you

- Whether you run the affected software, and where
- Whether an attacker can actually reach and exploit it
- The misconfigurations that never get a CVE number
- What it would cost the business, ranked into what to fix first

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