8.4

CVE-2026-109290: open-webui Cross-site Scripting

CVSS: 8.4v4.0HighAwaiting analysis
Published 12-10-2026Last modified 13-10-2026
Open JSON

Vulnerability summary

CVE-2026-109290 is a high (CVSS 8.4) Cross-site Scripting vulnerability in open-webui. EPSS estimates a 0.26% chance of exploitation in the next 30 days, higher than 16.1% of scored vulnerabilities.

Overall risk
34/100
0100
Medium · default modelHow is this calculated?
CVSS score
8.4/10
010
High · v4.0 (NVD)
EPSS score
0.26%
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 0.11.1 before 0.11.4 contains a stored cross-site scripting vulnerability in DocxPreview.svelte that allows authenticated users to execute script by uploading crafted DOCX attachments. Attackers can embed an OOXML altChunk HTML part or script-scheme hyperlink to steal a previewing administrator's session token from local storage and take over the instance.

CVSS metrics

4 scores · 2 sources · 2 versions

EPSS trend

Probability

0.26%

Chance of exploitation in the next 30 days

Percentile

16%

Versus all other CVEs

30-day change

Change unavailable

Change unavailable

13-10-202620-10-2026
EPSS score
0.26%

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