Read the docs
TI-2026-76666 Aliases CVE-2026-77936

Insecure default configuration in Letta exposes API and PostgreSQL

Priority HIGH 81CWE-1188Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Attack requirements
None
Impact type
—
Confidentiality · integrity · availability
High · High · High
Fix status
No fix listed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA.

Summary

Letta through 0.16.8 ships a compose.yaml with insecure defaults that leave its API and PostgreSQL port exposed. The file does not enable the secure server setting, so API routes are unauthenticated, and the database port uses superuser default credentials (CWE-1188). A remote unauthenticated attacker can run arbitrary Python, manage admin users, and run operating system commands through the database. A public exploit is linked in the references.

Written with Claude Haiku 5.5 from the sources below · 2026-10-28

Description from the CNA

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.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00589 48th percentileScored 2026-11-08
Public exploit Yes 1 exploit referenceTagged by the CNA
Fix No fix listed No fixed version in the sources yet

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
Yes
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
letta-ailettaup to 0.16.8—No fix listedCNA
  • letta Vendorletta-ai Affected up to 0.16.8 Fixed in — No fix listed CNA

Remediation

The sources list no fixed version for letta.

Written with Claude Haiku 5.5 from the sources below · 2026-10-28

Timeline

  1. 2026-10-20 Threatist record created from CVE-2026-77936
  2. 2026-10-20 CISA SSVC decision points changed
  3. 2026-10-20 Priority changed: MEDIUM → HIGH

References

Exploit 1

Other 2

  • TI-2026-76667 Letta lets API callers impersonate other users via user_id header CVSS 4.0HIGH 8.6
  • TI-2026-15517 letta-ai LettaBot API Status Route server.ts missing authentication CVSS 4.0MEDIUM 6.9
  • TI-2026-76668 Letta tool sandbox exposes server secrets to tool users CVSS 4.0HIGH 7.1
  • TI-2025-05511 letta-ai letta interface.py function_message eval injection CVSS 4.0MEDIUM 5.1

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences