CVE-2026-31950CWE-284

LibreChat's IDOR in SSE Stream Subscription Allows Reading Other Users' Chats

Medium · published March 27, 2026

CVSS v3.1
5.3
EPSS
0%
Percentile
19.5
In the wild
Unconfirmed
What it is

LibreChat is a ChatGPT clone with additional features. In versions 0.8.2-rc2 through 0.8.2-rc3, the SSE streaming endpoint `/api/agents/chat/stream/:streamId` does not verify that the requesting user owns the stream. Any authenticated user who obtains or guesses a valid stream ID can subscribe and read another user's real-time chat content, including messages, AI responses, and tool invocations. Version 0.8.2 patches the issue.

The record
Technical detail
CVSS v3.1
5.3 · MEDIUM
Vector
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N
CVSS v4.0
Not supplied
EPSS
0.00281 · 19.5th percentile
Weakness
CWE-284 · Improper Access Control
Published
2026-03-27T19:25Z
EPSS history
Timeline
  • 27 MAR 19:25Z
    LibreChat's IDOR in SSE Stream Subscription Allows Reading Other Users' Chats
    cvelistv5