GHSA-w5fx-cx7f-6vr9 is a high-severity (CVSS 7.5) CWE-835 vulnerability in mediawiki/core. 1 public exploit reference exists, so weaponization risk is real. A fix is available for mediawiki/core — see the affected versions and patch details below.
MediaWiki Denial of Service vulnerability
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for GHSA-w5fx-cx7f-6vr9.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
GHSA-w5fx-cx7f-6vr9 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 377,636 CVEs with a current EPSS score, this one falls in the 10–50% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
mediawiki/core🐘mediawiki/core🐘mediawiki/coreReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.
Description
An issue was discovered in ApiPageSet.php in MediaWiki before 1.35.12, 1.36.x through 1.39.x before 1.39.5, and 1.40.x before 1.40.1. It allows attackers to cause a denial of service (unbounded loop and RequestTimeoutException) when querying pages redirected to other variants with redirects and converttitles set.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | mediawiki/core | all versions | 1.35.12composer require mediawiki/core:^1.35.12 |
| 🐘Packagist | mediawiki/core | ≥ 1.36.0&&< 1.39.5 | 1.39.5composer require mediawiki/core:^1.39.5 |
| 🐘Packagist | mediawiki/core | ≥ 1.40.0&&< 1.40.1 | 1.40.1composer require mediawiki/core:^1.40.1 |
Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for mediawiki/core, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update mediawiki/core to 1.35.12 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-w5fx-cx7f-6vr9 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-w5fx-cx7f-6vr9 can be triaged on real exposure rather than presence alone.
Tailored to GHSA-w5fx-cx7f-6vr9. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-w5fx-cx7f-6vr9 in your dependencies?
O3 Security finds GHSA-w5fx-cx7f-6vr9 across Packagist dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.