dbcve.org
FedoraOperating system · Fedoraproject

CVE-2020-25828

MEDIUM · 6.1 CVSS v3.1 Published 2020-09-27
Fix available
A fix is available. Upgrade to 1.34.4 or later.
See remediation →
68/100
Remediation priority · Elevated
Remotely reachable No privileges

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 1.31.10 and 1.32.x through 1.34.x before 1.34.4. The non-jqueryMsg version of mw.message().parse() doesn't escape HTML. This affects both message contents (which are generally safe) and the parameters (which can be based on user input). (When jqueryMsg is loaded, it correctly accepts only whitelisted tags in message contents, and escapes all parameters. Situations with an unloaded jqueryMsg are rare in practice, but can for example occur for Special:SpecialPages on a wiki with no extensions installed.)

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's mw.message().parse() function in versions before 1.31.10 and 1.34.4 fails to escape HTML when the jqueryMsg library is unloaded. Since message parameters can contain user input, this enables XSS attacks via crafted parameters in specific contexts like Special:SpecialPages on wikis without extensions installed.

MitigationUpgrade MediaWiki to version 1.31.10, 1.32.x through 1.34.4, or later versions to receive the patch that properly escapes HTML in mw.message().parse() when jqueryMsg is not loaded.

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
FedoraOperating system
Affected:= 33
MediawikiCMS
Affected:>= 1.32.0, < 1.34.4= 1.31.10

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
Required
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None

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

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 MediaWiki version
    Check the version file in your MediaWiki installation (e.g., includes/Defines.php or Special:Version page). Compare the version number against the affected ranges: 1.31.10, or 1.32.0 through any version less than 1.34.4.
    Affected if Your installed MediaWiki version is exactly 1.31.10, or falls between 1.32.0 and 1.34.3 inclusive.
  2. Identify if jqueryMsg library is loaded
    Examine your MediaWiki JavaScript configuration and resource loader settings. Check if jqueryMsg module is present and loaded in the page output for the affected context (Special:SpecialPages). Inspect the page source for jquery.msg or related jqueryMsg references.
    Affected if The jqueryMsg library is NOT loaded or is disabled on your wiki, which is more common on minimal installations without extensions.
  3. Check for presence of extensions
    Review your LocalSettings.php file for $wgExtensionCredits and verify whether any extensions are installed. Also check the Special:Version page to enumerate installed extensions.
    Affected if Your wiki has NO extensions installed, as the vulnerability specifically notes this condition (wikis without extensions installed).
  4. Inspect affected endpoint
    Access Special:SpecialPages on your wiki and view the page source. Look for mw.message().parse() calls in the JavaScript that may be processing user-controllable parameters without proper HTML escaping.
    Affected if The Special:SpecialPages page renders and contains unescaped HTML in message parameter output, indicating the vulnerability is present and exploitable.

You are affected if your MediaWiki version is exactly 1.31.10 or between 1.32.0 and 1.34.3, AND the jqueryMsg library is unloaded, AND your wiki lacks extensions (or has minimal extensions), allowing XSS via crafted parameters in Special:SpecialPages.

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.

From vendor data
Upgrade available Upgrade to 1.34.4 or later
Fixed in 1.34.4
Interim mitigation

Upgrade MediaWiki to version 1.31.10, 1.32.x through 1.34.4, or later versions to receive the patch that properly escapes HTML in mw.message().parse() when jqueryMsg is not loaded.

Fix this in Fedora Scoped from the published advisory
  • Consultation2.0 h
  • Implementation1.0 h
  • Testing3.0 h
  • Review / QA1.0 h
7.0 hours of engineering $1,210
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Scan for this in your stack

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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-2020-25828 in production — separate from our analysis above.

No notes yet

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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