CVE-2026-77938
Deferred Deferred - Pending Action

LocalSandbox Environment Variable Disclosure in Letta

Publication date: 2026-10-20

Last updated on: 2026-10-20

Assigner: VulnCheck

Description
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.

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Meta Information

Published
2026-10-20
Last Modified
2026-10-20
Generated
2026-11-09
AI Q&A
2026-10-20
EPSS Evaluated
2026-11-07
NVD
CVE-2026-77938
EUVD
EUVD-2026-104694

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
letta-ai letta 0

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Exploitability

CWE
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KEV
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CWE ID Description
CWE-526 The product uses an environment variable to store unencrypted sensitive information.

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Executive Summary

CVE-2026-77938 is an information disclosure vulnerability in Letta versions up to 0.16.8. It occurs because LocalSandbox subprocesses inherit the full server environment, allowing users to read sensitive server secrets like LETTA_PG_URI, POSTGRES_PASSWORD, and provider API keys by executing code via POST /v1/tools/run or custom tools. This can lead to unauthorized access to cross-tenant database data.

Detection Guidance

Check for unauthorized access to environment variables like LETTA_PG_URI, POSTGRES_PASSWORD, or provider API keys. Monitor POST /v1/tools/run endpoints for unusual tool execution requests. Inspect LocalSandbox subprocesses for inherited server environment variables.

Impact Analysis

If you use Letta through 0.16.8, attackers with access to the tool execution endpoint could steal database credentials and API keys. This may allow them to access sensitive data across multiple tenants, leading to data breaches, unauthorized modifications, or further exploitation of your systems.

Compliance Impact

This vulnerability likely violates GDPR and HIPAA requirements for protecting sensitive data. Unauthorized access to database credentials and cross-tenant data could result in non-compliance, leading to legal penalties, reputational damage, and loss of trust in your systems.

Mitigation Strategies

Upgrade Letta to a version beyond 0.16.8 where the issue is fixed. Restrict access to POST /v1/tools/run endpoints. Remove sensitive environment variables from LocalSandbox subprocess inheritance. Rotate exposed credentials like POSTGRES_PASSWORD and provider API keys.

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