8.5

CVE-2026-109291: open-webui Cross-site Scripting

CVSS: 8.5v4.0HighAwaiting analysis
Published 12-10-2026Last modified 18-10-2026
Open JSON

Vulnerability summary

CVE-2026-109291 is a high (CVSS 8.5) Cross-site Scripting vulnerability in open-webui. EPSS estimates a 0.28% chance of exploitation in the next 30 days, higher than 19.1% of scored vulnerabilities.

Overall risk
34/100
0100
Medium · default modelHow is this calculated?
CVSS score
8.5/10
010
High · v4.0 (NVD)
EPSS score
0.28%
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. 18-10-2026
    Last modifiedVulnerability information updated.

Description

Open WebUI from 0.6.33 before 0.11.4 contains a cross-site scripting vulnerability that allows authenticated users to execute script in victims' sessions by storing javascript: URLs in citation embed_url fields. Attackers can share a crafted chat whose citation, when clicked, is passed to window.open, letting them steal localStorage.token and act as the victim.

CVSS metrics

4 scores · 2 sources · 2 versions

EPSS trend

Probability

0.28%

Chance of exploitation in the next 30 days

Percentile

19%

Versus all other CVEs

30-day change

Change unavailable

Change unavailable

13-10-202620-10-2026
EPSS score
0.28%

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