Description
Letta through 0.16.8 contains an authentication bypass vulnerability that allows API callers to impersonate other users by supplying a self-asserted user_id HTTP header. Attackers can set user_id to another tenant's ID, even with LETTA_SERVER_SECURE enabled, to read and modify that user's agents, memory and configuration.
Published: 2026-10-20
Score: 8.6 High
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

No vendor fix or workaround currently provided.

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Tracking

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Advisories

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History

Tue, 20 Oct 2026 01:15:00 +0000

Type Values Removed Values Added
Description Letta through 0.16.8 contains an authentication bypass vulnerability that allows API callers to impersonate other users by supplying a self-asserted user_id HTTP header. Attackers can set user_id to another tenant's ID, even with LETTA_SERVER_SECURE enabled, to read and modify that user's agents, memory and configuration.
Title Letta through 0.16.8 Cross-Tenant Impersonation via user_id Header
First Time appeared Letta
Letta letta
Weaknesses CWE-639
CPEs cpe:2.3:a:letta:letta:*:*:*:*:*:*:*:*
Vendors & Products Letta
Letta letta
References
Metrics cvssV3_1

{'score': 8.1, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N'}

cvssV4_0

{'score': 8.6, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N'}

Subscriptions

Letta Letta
cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published:

Updated: 2026-10-20T00:46:14.829Z

Reserved: 2026-08-21T17:52:36.080Z

Link: CVE-2026-77937

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-10-20T01:17:20.263

Modified: 2026-10-20T01:17:20.263

Link: CVE-2026-77937

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses
  • CWE-639

    Authorization Bypass Through User-Controlled Key