CVE-2026-109284CWE-862broken-access-control

CVE-2026-109284

Medium · published October 12, 2026

CVSS v3.1
4.3
EPSS
0%
Percentile
10.6
In the wild
Unconfirmed
What it is

Open WebUI from 0.11.0 before 0.11.4 contains an improper authorization vulnerability in the chat fork handler, which places forked chats in the source chat's folder without checking folder write access. Shared folder members downgraded to read-only can call POST /api/v1/chats/{id}/fork on chats they created there while they had write access, inserting attacker-controlled chats visible to the folder owner and members.

The record
Technical detail
CVSS v3.1
4.3 · MEDIUM
Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
CVSS v4.0
5.3 · CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N
EPSS
0.00209 · 10.6th percentile
Weakness
CWE-862 · Missing Authorization
Published
2026-10-12T21:17Z
References (2)
https://github.com/open-webui/open-webui/security/advisories/GHSA-6fjc-5cg3-mgvh · [email protected]https://www.vulncheck.com/advisories/open-webui-0.11.0-before-0.11.4-improper-authorization-via-chat-fork-endpoint · [email protected]
EPSS history
Timeline
  • 14 OCT 03:27Z
    EPSS moved — → 0%
    epss
  • 12 OCT 16:04Z
    Open WebUI 0.11.0 before 0.11.4 Improper Authorization via Chat Fork Endpoint
    cvelistv5
  • 12 OCT 16:04Z
    Open WebUI 0.11.0 before 0.11.4 Improper Authorization via Chat Fork Endpoint
    cvelistv5