6.9

CVE-2026-39838: wikimedia foundation mediawiki - proofreadpage extension Cross-site Scripting

CVSS: 6.9v4.0MediumAwaiting analysis
Published 07-04-2026Last modified 08-04-2026
Open JSON

Vulnerability summary

CVE-2026-39838 is a medium (CVSS 6.9) Cross-site Scripting vulnerability in wikimedia foundation mediawiki - proofreadpage extension. EPSS estimates a 0.45% chance of exploitation in the next 30 days, higher than 38% of scored vulnerabilities.

Overall risk
28/100
0100
Medium · default modelHow is this calculated?
CVSS score
6.9/10
010
Medium · v4.0 (CVE.org)
EPSS score
0.45%
0%100%
Low · +0.05 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Timeline

  1. 07-04-2026
    PublishedVulnerability first disclosed.
  2. 08-04-2026
    Last modifiedVulnerability information updated.

Description

Improper neutralization of input during web page generation ('cross-site scripting') vulnerability in Wikimedia Foundation MediaWiki - ProofreadPage Extension allows XSS Targeting Non-Script Elements. The issue has been remediated on the `master` branch, and in the release branches for MediaWiki versions 1.43, 1.44, and 1.45.

CVSS metrics

2 scores · 2 sources · 1 version

EPSS trend

Probability

0.45%

Chance of exploitation in the next 30 days

Percentile

38%

Versus all other CVEs

30-day change

+0.05 pp

From 0.40% on 20-09-2026

20-09-202620-10-2026
EPSS score
0.45%

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

Wikimedia foundation1 product

1 vendor · 1 product

References

2 links