High
Letta through 0.16.8 Cross-Tenant Impersonation via user_id Header
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.
Announced Group revision 1
Original source ↗CVE-2026-77937
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2026-77937
letta
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"repo": "https://github.com/letta-ai/letta",
"vendor": "letta-ai",
"product": "letta",
"versions": [
{
"status": "affected",
"version": "0",
"versionType": "semver",
"lessThanOrEqual": "0.16.8"
}
],
"packageURL": "pkg:pypi/letta",
"collectionURL": "https://pypi.org",
"defaultStatus": "unaffected"
}
]- Related CVEs
- CVE-2026-77937
Source reference:
/cveMetadata/cveId
Publisher severity
high
Source reference: /containers/cna/metrics
- Event
- #42188 · Revision 1
- Added to Heist Feed
- Publisher date