CVE-2026-77938

MEDIUM 6.5

Letta through 0.16.8 Credential Exposure via Tool Sandbox Environment Inheritance

CVSS Score

6.5

EPSS Score

0.0%

EPSS Percentile

0th

Letta through 0.16.8 contains an information disclosure vulnerability that allows users running tools to read server secrets because LocalSandbox subprocesses inherit the full server environment. Attackers can run code via POST /v1/tools/run or custom tools to read LETTA_PG_URI, POSTGRES_PASSWORD, and provider API keys, then access cross-tenant database data.

CWE	CWE-526
Vendor	letta-ai
Product	letta
Published	Oct 20, 2026

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CVSS v3 Breakdown

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

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

None

Availability

None

Affected Versions

letta-ai / letta

0 ≤ 0.16.8

References

NVD ↗ CVE.org ↗ EPSS Data ↗

lasso.security: https://www.lasso.security/vulnerability-database/cve-2026-77938 github.com: https://github.com/letta-ai/letta/blob/1131535716e8a31c9a437f8695e25ac98f203a24/letta/services/tool_sandbox/base.py#L487 vulncheck.com: https://www.vulncheck.com/advisories/letta-through-0.16.8-credential-exposure-via-tool-sandbox-environment-inheritance

Credits

Noy Pearl Michael Sromin Ophir Dror