CVE-2025-61638: Improper Neutralization of Input During Web Page Generation (XSS or 'Cross-site Scripting') vulnerability in W

Routine

MEDIUM 4.8UPGRADEUPGRADE

CVE-2025-61638 is a medium-severity flaw (CVSS 4.8) affecting mediawiki, parsoid. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Improper Neutralization of Input During Web Page Generation (XSS or 'Cross-site Scripting') vulnerability in Wikimedia Foundation MediaWiki, Wikimedia Foundation Parsoid. This vulnerability is associated with program files includes/parser/Sanitizer.Php, src/Core/Sanitizer.Php. This issue affects MediaWiki: from * before 1.39.14, 1.43.4, 1.44.1; Parsoid: from * before 0.16.6, 0.20.4, 0.21.1.

Why this priority

No elevated risk signals yet

A fixed release or distro patch exists.

Risk facts

CVSS score	4.8 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	High
User interaction	Required
EPSS exploit chance	0.3% (top 81%)
CISA exploited list	No
Weakness	CWE-79
Published	2026-02-03
Last modified	2026-06-17

Publisher (CNA): wikimedia-foundation · Vendor: mediawiki · wikimedia

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-02-03 00:16 UTCPublished CVE record published
2026-06-17 09:50 UTCUpdated Record last modified

mediawiki mediawiki UPGRADE

Affected: < 1.39.14 · >= 1.39.15 and < 1.43.4 · >= 1.43.5 and < 1.44.1

Fixed in: 1.39.14, 1.43.4, 1.44.1

Safe to downgrade to: a release before 1.39.15

1. Check installed version

apt-cache policy mediawiki || rpm -q mediawiki || mediawiki --version

2. UPGRADE to 1.39.14 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade mediawiki

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade mediawiki

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 1.39.15 (Debian / Ubuntu)

apt-cache madison mediawiki sudo apt install mediawiki=<VERSION_BEFORE_1.39.15> sudo apt-mark hold mediawiki

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list mediawiki sudo dnf downgrade mediawiki-<VERSION_BEFORE_1.39.15> sudo dnf versionlock add mediawiki

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

wikimedia parsoid UPGRADE

Affected: < 0.16.6 · > 0.16.6 and < 0.20.4 · > 0.20.4 and < 0.21.1

Fixed in: 0.16.6, 0.20.4, 0.21.1

Safe to downgrade to: no unaffected older release

1. Check installed version

npm ls parsoid

2. UPGRADE to 0.16.6

npm install parsoid@">=0.16.6"

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2025-61638?

mediawiki: upgrade to 1.39.14, 1.43.4, 1.44.1; parsoid: upgrade to 0.16.6, 0.20.4, 0.21.1. Exact commands for each OS are on this page.

Is CVE-2025-61638 being exploited?

CVE-2025-61638 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2025-61638 affect?

CVE-2025-61638 affects mediawiki, parsoid. Severity is medium (CVSS 4.8). Improper Neutralization of Input During Web Page Generation (XSS or 'Cross-site Scripting') vulnerability in Wikimedia Foundation MediaWiki, Wikimedia Foundation Parsoid. This vulnerability is associated with program files includes/parser/S

How urgent is CVE-2025-61638?

Priority 22/100. No elevated risk signals yet.

Software pages

PHP vulnerabilities

Related CVEs

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CVE-2026-34093 MEDIUM 5.3 UPGRADE Exposure of Sensitive Information to an Unauthorized Actor vulnerability in Wikimedia Foundation MediaWiki.
CVE-2026-34095 MEDIUM 6.1 UPGRADE Vulnerability in Wikimedia Foundation MediaWiki. This vulnerability is associated with program files include

References

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