dbcve.org
MediawikiCMS

CVE-2021-46149

HIGH · 7.5 CVSS v3.1 Published 2022-01-10
Fix available
A fix is available. Upgrade to 1.35.5 / 1.36.3 or later.
See remediation →
84/100
Remediation priority · High
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
An issue was discovered in MediaWiki before 1.35.5, 1.36.x before 1.36.3, and 1.37.x before 1.37.1. A denial of service (resource consumption) can be accomplished by searching for a very long key in a Language Name Search.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

MediaWiki before versions 1.35.5, 1.36.3, and 1.37.1 contains a denial of service vulnerability in the Language Name Search feature. Attackers can cause excessive resource consumption by searching for an excessively long key, likely triggering inefficient processing or memory issues.

MitigationUpgrade MediaWiki to version 1.35.5, 1.36.3, 1.37.1 or later. As a temporary workaround, consider rate-limiting or restricting the language name search functionality.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
MediawikiCMS
Affected:< 1.35.5>= 1.36.0, < 1.36.3>= 1.37.0, < 1.37.1

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Determine installed MediaWiki version
    Locate and read the version file in your MediaWiki installation (typically includes a version number or RELEASE-NOTES file), or check the Special:Version page on your wiki if you have admin access
    Affected if The installed version falls within < 1.35.5, >= 1.36.0 and < 1.36.3, or >= 1.37.0 and < 1.37.1
  2. Verify Language Name Search feature is accessible
    Confirm that the Language Name Search functionality is available on your MediaWiki installation. This feature is typically accessed through language-related special pages or API endpoints
    Affected if The Language Name Search feature is enabled and accessible to users (this is the default state in vulnerable versions)
  3. Check for unusual resource consumption patterns
    Review server logs and resource monitoring data for signs of excessive CPU or memory usage correlated with language search queries, particularly searches containing unusually long strings
    Affected if Logs show repeated or sustained high resource consumption tied to language name search requests with long input strings
  4. Inspect API or search logs for long query patterns
    Examine access logs, API logs, or application logs for requests to language search endpoints containing abnormally long search keys
    Affected if You observe API or web requests with excessively long search parameters targeting the language name search feature

Your environment is affected if you are running any MediaWiki version below 1.35.5, between 1.36.0-1.36.2, or between 1.37.0-1.37.0, and the Language Name Search feature is accessible to users.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 1.35.5 / 1.36.3 / 1.37.1 or later
Fixed in 1.35.51.36.31.37.1
Interim mitigation

Upgrade MediaWiki to version 1.35.5, 1.36.3, 1.37.1 or later. As a temporary workaround, consider rate-limiting or restricting the language name search functionality.

Recommended fix High confidence

Upgrade to MediaWiki 1.35.5, 1.36.3, or 1.37.1 (depending on your current branch)

  1. 1. Backup your MediaWiki installation and database before proceeding with the upgrade.
  2. 2. Determine your current MediaWiki version by checking the includes/DefaultSettings.php file or the Special:Version page.
  3. 3. If you are on the 1.35.x branch, upgrade to version 1.35.5 or later.
  4. 4. If you are on the 1.36.x branch, upgrade to version 1.36.3 or later.
  5. 5. If you are on the 1.37.x branch, upgrade to version 1.37.1 or later.
  6. 6. Download the appropriate MediaWiki release from https://www.mediawiki.org/wiki/Download or use your package manager.
  7. 7. Extract the new version files, replacing the old installation while preserving your LocalSettings.php and any custom extensions.
  8. 8. Run the update script (php maintenance/update.php) if necessary.
Caveat Review the MediaWiki release notes for your target version to check for any breaking changes or database schema updates that may require attention.

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Mediawiki Scoped from the published advisory
  • Consultation2.0 h
  • Implementation3.0 h
  • Testing2.0 h
  • Review / QA1.0 h
8.0 hours of engineering $1,420
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,272.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2021-46149 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

Get it on GitHub Scan in the browser

References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2021-46149 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data