CVE-2026-39838
CWE-79Published: April 7, 2026· Updated: Apr 8, 2026
Official 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.
Technical Analysis
CVE-2026-39838 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.
The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.
From a weakness classification perspective (CWE-79): Cross-site scripting (XSS) vulnerabilities allow attackers to inject malicious scripts into web pages viewed by other users.
CVSS v3.1 Vector Breakdown
Exploit & PoC Resources
All References (2)
Quick Facts
Related CVEs (CWE-79)
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2026-39838 in threat intel feeds
- →Review IDS/IPS signatures for exploitation attempts