FedoraOperating system · Fedoraproject
CVE-2021-45471
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 · uneditedIn MediaWiki through 1.37, blocked IP addresses are allowed to edit EntitySchema items.
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 confidenceIn MediaWiki through 1.37, the software's IP-based blocking mechanism fails to apply to EntitySchema items. Blocked IP addresses can still edit EntitySchema items despite being blocked from other edit operations, representing an authorization bypass where the EntitySchema extension does not properly enforce IP blocks that are applied to prevent editing.
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
= 35<= 1.37CVSS 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
- Low
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/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 checksWork through these to decide whether this CVE applies to you.
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Identify MediaWiki versionCheck the installed MediaWiki version through the admin interface (Special:Version) or by inspecting includes/DefaultSettings.php for $wgVersionAffected if version is 1.37 or lower
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Confirm EntitySchema extension is presentCheck if the EntitySchema extension is installed by looking for the EntitySchema directory in the extensions folder, or via Special:Version page listing loaded extensionsAffected if EntitySchema extension is listed as installed
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Verify IP blocking is configuredCheck if any IP-based blocks exist in the database (ipblocks table) or if $wgBlockAllowsUTEdit is false in LocalSettings.phpAffected if IP blocking is actively in use (there are blocked IPs or block settings enabled)
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Check for vulnerable configurationReview LocalSettings.php for $wgBlockDisablesLogin and confirm EntitySchema edit permissions are not overridden to enforce blocksAffected if EntitySchema extension is enabled and IP blocks are configured, but no explicit enforcement of IP blocks on EntitySchema edits exists in the configuration
You are affected if running MediaWiki version 1.37 or earlier with the EntitySchema extension enabled while using IP-based blocking.
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 dataApply the appropriate MediaWiki security patch or update to a version beyond 1.37 that enforces IP-based blocks on EntitySchema edit operations. Until patched, consider disabling EntitySchema editing or implementing additional access controls at the web server level for known malicious IPs.
Fix this in Fedora
Scoped from the published advisory
- Consultation4.0 h
- Implementation8.0 h
- Testing4.0 h
- Review / QA3.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $5,408.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-45471 — 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-2021-45471 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
- No spam, self-promotion, credentials, or personal data