CVE-2026-77936

CRITICAL 9.8

Letta through 0.16.8 Insecure Default Configuration Unauthenticated API and PostgreSQL Access

CVSS Score

9.8

EPSS Score

0.0%

EPSS Percentile

0th

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.

CWE	CWE-1188
Vendor	letta-ai
Product	letta
Published	Oct 20, 2026

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CVSS v3 Breakdown

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Affected Versions

letta-ai / letta

0 ≤ 0.16.8

References

NVD ↗ CVE.org ↗ EPSS Data ↗

lasso.security: https://www.lasso.security/vulnerability-database/cve-2026-77936 github.com: https://github.com/letta-ai/letta/blob/1131535716e8a31c9a437f8695e25ac98f203a24/compose.yaml#L17 github.com: https://github.com/letta-ai/letta/blob/1131535716e8a31c9a437f8695e25ac98f203a24/letta/server/rest_api/app.py#L799 vulncheck.com: https://www.vulncheck.com/advisories/letta-through-0.16.8-insecure-default-configuration-unauthenticated-api-and-postgresql-access

Credits

Noy Pearl Michael Sromin Ophir Dror