CVE-2015-6736
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 · uneditedThe Quiz extension for MediaWiki allows remote attackers to cause a denial of service via regex metacharacters in a regular expression.
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 · moderate confidenceThe Quiz extension for MediaWiki contains a Regular Expression Denial of Service (ReDoS) vulnerability. Remote attackers can craft input containing regex metacharacters that cause the vulnerable regular expression to exhibit catastrophic backtracking, consuming excessive CPU resources and rendering the service unavailable.
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 dataall versionsCVSS 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
- Authentication
- None
- Confidentiality
- None
- Integrity
- None
- Availability
- Partial
AV:N/AC:L/Au:N/C:N/I:N/A:P
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 checksWork through these to decide whether this CVE applies to you.
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Confirm MediaWiki installationCheck for the presence of MediaWiki by locating the 'mediawiki' directory or the 'LocalSettings.php' configuration file in your web root.Affected if MediaWiki is installed on the server.
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Identify if Quiz extension is installedLook for the Quiz extension directory under 'mediawiki/extensions/Quiz' or check your 'LocalSettings.php' for lines containing 'wfLoadExtension' or 'Quiz' configuration.Affected if The Quiz extension directory exists or Quiz configuration is present in LocalSettings.php.
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Verify Quiz extension is enabledSearch LocalSettings.php for '$wgEnableQuiz' set to true, or 'wfLoadExtension( 'Quiz' );' or similar extension loading statements.Affected if The extension is loaded or enabled in the MediaWiki configuration.
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Confirm quiz functionality is accessibleTest accessing the quiz feature by navigating to a page that uses the Quiz tag (e.g., Special:Quiz) or by checking for quiz-related special pages in the wiki.Affected if Quiz special pages or quiz functionality is accessible on the wiki.
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Review Quiz regex processing codeExamine the Quiz extension PHP files for preg_match, preg_match_all, or similar regex operations that process user input without proper escaping of regex metacharacters.Affected if The Quiz extension contains regex code that processes user-submitted input.
If MediaWiki is running with the Quiz extension enabled and accessible, the environment is affected since all versions of the Quiz extension are vulnerable to ReDoS via crafted regex metacharacters.
Generated from the published advisory. Verify against your own configuration.
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 dataRemediate by either refactoring the vulnerable regex to use atomic groups or possessive quantifiers, or by implementing input validation to filter/escape regex metacharacters before they reach the regex engine.
- Consultation2.0 h
- Implementation4.0 h
- Testing3.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,088.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2015-6736 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2015-6736 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- 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
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