Security readout for executives and security teams
Plain-English summary
This flaw lets someone bypass a MediaWiki AbuseFilter rule that should stop creation of a blocked page title. The business impact is limited integrity loss: unwanted or policy-blocked pages could be created, but the sources do not indicate data theft, service outage, or active exploitation.
Executive priority
Handle in normal patch cycles unless the organization relies heavily on AbuseFilter for public-content governance. Escalate priority for public wikis where blocked-title creation could create compliance, trust, or moderation issues.
Technical view
MediaWiki before 1.35.5, 1.36.3, and 1.37.1 mishandled the EditFilterMergedContent hook return value. Through Special:ChangeContentModel, a title blocked by AbuseFilter could still be created. CVSS 3.1 is 5.3 with network access, low complexity, no privileges, no user interaction, and low integrity impact.
Likely exposure
Exposure is most relevant for MediaWiki sites on affected versions that rely on AbuseFilter to prevent creation of specific titles. Publicly reachable wikis have higher practical exposure because the CVSS vector requires only network access and no authentication.
Exploitation context
The provided bundle does not show CISA KEV listing or any cited evidence of active exploitation. The issue is a policy-control bypass, not a remote code execution or data disclosure flaw, based on the supplied CVSS and description.
Researcher notes
The source bundle names MediaWiki versions and the hook-handling weakness but provides limited affected-product metadata. Avoid assuming impact beyond AbuseFilter title-block bypass through Special:ChangeContentModel unless confirmed by vendor advisories or local testing.
Mitigation direction
- Upgrade MediaWiki to 1.35.5, 1.36.3, 1.37.1, or later supported versions.
- For Gentoo-managed systems, review and follow GLSA 202305-24 guidance.
- Check current Wikimedia/MediaWiki vendor guidance for any branch-specific instructions.
- Prioritize public wikis that depend on AbuseFilter for title creation controls.
Validation and detection
- Inventory all MediaWiki instances and record exact core versions.
- Confirm affected branches are upgraded beyond the fixed versions listed in the CVE.
- Review whether AbuseFilter is used to block page title creation.
- Review logs for unexpected Special:ChangeContentModel activity involving blocked titles.
- Check for pages whose titles should have been blocked by AbuseFilter rules.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-754: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2021-44856 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Medium
- CVSS
- 5.3 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N3.91.4Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
5.3MediumVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
Source materials
- CVE List V5 sourceCVE List V5
- https://phabricator.wikimedia.org/T271037CVE reference
- https://security.gentoo.org/glsa/202305-24CVE reference
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Improper Check for Unusual or Exceptional Conditions
Improper Check for Unusual or Exceptional Conditions represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.