Vulnerability details

CVE-2026-77936

letta-ai letta

Letta through 0.16.8 Insecure Default Configuration Unauthenticated API and PostgreSQL Access

CVSS 4.0

9.3Critical

Official description

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.

CVSS scores

Score	Version	Source	Vector
9.3Critical	4.0	CVEProject cvelistV5 (CNA) (VulnCheck)	`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`
9.8Critical	3.1	CVEProject cvelistV5 (CNA) (VulnCheck)	`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`

Affected products

Vendor	Product	Versions	Source
letta-ai	letta	v ≤ 0.16.8	CVEProject cvelistV5 (CNA)

References and advisories

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

Kolun on Telegram @kolunsec Exploited CVEs, key news and a daily digest Alerts for this product's next CVEsFollow the product to get new vulnerabilities on Telegram.

Details

Published: 2026-10-20
Last updated: 2026-10-20
State: Published
Assigner (CNA): VulnCheck
Kolun priority: 36 · Medium

Exploit prediction (EPSS)

0.58%

Probability of exploitation in 30 days

48.3%

Percentile (among all CVEs)

SSVC assessment (CISA)

Automatable: Yes
Exploitation: Proof of concept
Technical impact: Total

Weaknesses (CWE)

CWE-1188
Initialization of a Resource with an Insecure Default