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CVE Record

CVE-2020-25812: An issue was discovered in MediaWiki 1.34.x before 1.34.4.

An issue was discovered in MediaWiki 1.34.x before 1.34.4. On Special:Contributions, the NS filter uses unescaped messages as keys in the option key for an HTMLForm specifier. This is vulnerable to a mild XSS if one of those messages is changed to include raw HTML.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysislow

Security readout for executives and security teams

Plain-English summary

MediaWiki 1.34.x before 1.34.4 had a mild cross-site scripting issue in the Special:Contributions namespace filter. It depends on a related message being changed to include raw HTML, so urgency is lower than a broadly reachable unauthenticated flaw, but public-facing wikis should still update.

Executive priority

Handle during normal patching unless the organization exposes MediaWiki publicly and heavily customizes interface messages. Public wikis on 1.34.x before 1.34.4 should be updated promptly to reduce avoidable browser-side risk.

Technical view

Special:Contributions used unescaped MediaWiki messages as keys in an HTMLForm option specifier for the namespace filter. If one of those messages contained raw HTML, the page could render unsafe content. The source bundle identifies MediaWiki 1.34.x before 1.34.4 as affected.

Likely exposure

Exposure is likely limited to MediaWiki deployments on the 1.34.x branch before 1.34.4, particularly where interface or localization messages related to the namespace filter were modified. The bundle does not identify other affected branches or products.

Exploitation context

The source bundle does not report active exploitation, and CISA KEV status is false. The described condition requires a relevant message to include raw HTML, making practical exposure dependent on site configuration and message changes.

Researcher notes

Evidence is narrow: the CVE text describes a mild XSS condition and the affected range, but the bundle provides no CVSS, CWE, exploit report, or broad product matrix. Avoid expanding scope beyond MediaWiki 1.34.x before 1.34.4.

Mitigation direction

  • Upgrade MediaWiki 1.34.x deployments to version 1.34.4 or later.
  • Review Wikimedia and distribution advisories for package-specific update guidance.
  • Audit customized interface messages related to Special:Contributions namespace filtering.
  • Limit changes to interface messages to trusted administrative workflows.

Validation and detection

  • Inventory MediaWiki instances and confirm whether any run 1.34.x before 1.34.4.
  • Check whether Special:Contributions namespace filter messages were locally customized.
  • Confirm deployed packages include the vendor or distribution security update.
  • Review web security monitoring for suspicious script execution reports on wiki pages.
Prepared
Confidence
medium
Sources
6

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

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0CVSS vectors
0Timeline events
0ADP providers
5Source links

CVSS and timeline data

No CVSS vectors or timeline events were available in the normalized CVE source material.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
n/an/an/aListed
Weakness

CWE details

No CWE listed

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