5.3

CVE-2026-109284: open-webui Missing Authorization

CVSS: 5.3v4.0MediumAwaiting analysis
Published 12-10-2026Last modified 13-10-2026
Open JSON

Vulnerability summary

CVE-2026-109284 is a medium (CVSS 5.3) Missing Authorization vulnerability in open-webui. EPSS estimates a 0.21% chance of exploitation in the next 30 days, higher than 10.4% of scored vulnerabilities.

Overall risk
21/100
0100
Low · default modelHow is this calculated?
CVSS score
5.3/10
010
Medium · v4.0 (NVD)
EPSS score
0.21%
0%100%
Low · Change unavailable
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Timeline

  1. 12-10-2026
    PublishedVulnerability first disclosed.
  2. 13-10-2026
    Last modifiedVulnerability information updated.

Description

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.

CVSS metrics

4 scores · 2 sources · 2 versions

EPSS trend

Probability

0.21%

Chance of exploitation in the next 30 days

Percentile

10%

Versus all other CVEs

30-day change

Change unavailable

Change unavailable

13-10-202620-10-2026
EPSS score
0.21%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Open-webui1 product

1 vendor · 1 product

References

2 links