CVE-2026-39838

MEDIUMNVD 6.9Elevated

6.9

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 v3: 6.9
EG Score: 0.0(none)
EPSS: 21.0%
KEV: Not listed

Published

April 7, 2026

Last Modified

April 8, 2026

References (2)

c4f26cc8-17ff-4c99-b5e2-38fc1793eacchttps://gerrit.wikimedia.org/r/q/Idd51e18479b32b7176b43ff74ca1c49d6bdd0628
c4f26cc8-17ff-4c99-b5e2-38fc1793eacchttps://phabricator.wikimedia.org/T406088

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

CWE-79Cross-site Scripting (XSS)

Data Freshness Timeline

(refreshed 15× in last 7d / 20× in last 30d)

Every time one of our enrichment pipelines (NVD, MITRE cvelistV5, EPSS, CISA KEV, GHSA, OSV, vendor advisories) ran against this CVE. Most recent first.

2026-05-31 22:30 UTCepss_batch
2026-05-31 22:30 UTCepss_batch
2026-05-31 00:16 UTCepss_batch
2026-05-31 00:16 UTCepss_batch
2026-05-31 00:16 UTCepss_batch
2026-05-29 13:44 UTCepss_batch
2026-05-29 13:44 UTCepss_batch
2026-05-28 13:44 UTCepss_batch
2026-05-28 13:44 UTCepss_batch
2026-05-28 13:44 UTCepss_batch
2026-05-27 13:40 UTCepss_batch
2026-05-27 13:40 UTCepss_batch
2026-05-27 13:40 UTCepss_batch
2026-05-26 07:18 UTCepss_batch
2026-05-26 07:18 UTCepss_batch
2026-05-20 22:38 UTCepss_batch
2026-05-20 22:38 UTCepss_batch
2026-05-20 18:36 UTCEG score recompute
2026-05-20 18:36 UTCGHSA enrichment
2026-05-20 11:22 UTCepss_batch

Frequently asked(5)

What is CVE-2026-39838?

CVE-2026-39838 is a medium vulnerability published on April 7, 2026. 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…

When was CVE-2026-39838 disclosed?

CVE-2026-39838 was first published in the National Vulnerability Database on April 7, 2026, with the most recent update on April 8, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.

Is CVE-2026-39838 actively exploited?

CVE-2026-39838 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 21.0% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.

What is the CVSS score of CVE-2026-39838?

CVE-2026-39838 has a CVSS v3 base score of 6.9 (NVD). EchelonGraph synthesises NVD + CISA KEV + FIRST EPSS + GHSA into a combined EG score of 0.0.

How do I remediate CVE-2026-39838?

Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-39838, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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CVE-2026-39838

📅 Published

🔄 Last Modified

🔗 References (2)

Weakness Classification(1)

Data Freshness Timeline

❓ Frequently asked(5)

Dependency Blast Radius

Is Your Infrastructure Affected by CVE-2026-39838?

🔗 Related CVEs(same CWE)

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Published

Last Modified

References (2)

Frequently asked(5)

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