Vulnerability in MediaWiki (CVE-2021-42045)

Summary

Vulnerability in MediaWiki (CVE-2021-42045). Risk of unauthorized operations or information disclosure. Exploitable via User-Agent header.

Original description

The description as published by the source.

An issue was discovered in SecurePoll in the Growth extension in MediaWiki through 1.36.2. Simple polls allow users to create alerts by changing their User-Agent HTTP header and submitting a vote.

Source: OSV.dev (Open Source Vulnerabilities) NVD OSV

Auto-generated summary

Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.

A vulnerability tracked as CVE-2021-42045 has been found in MediaWiki.
Attackers can target a specific entry point like User-Agent header over the network to misuse the product.
Risk of unauthorized operations or information disclosure.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "MediaWiki CVE-2021-42045" on the vendor's site.

CVE-2021-42045 (MediaWiki)
Attack vector: remote (network-reachable)
Attack surface: User-Agent header
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.

❓ What is the problem

A vulnerability (unclassified) exists in MediaWiki. Attackers reach the vulnerable code path via User-Agent header.

📍 Affected scope

Check the vendor advisory for the affected versions of MediaWiki. Attack surface: User-Agent header.

🔥 Severity

Severity: ?. Risk of unauthorized operations or information disclosure.

🔧 How to fix

Update to the patched release per vendor advisory.

🛡️ Workaround

Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.

🔍 Detection

Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'MediaWiki' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.

Response actions

Concrete steps and command examples for SOC/SRE teams to execute in order

1
Identify exposure identify
```
grep -r 'MediaWiki' . | grep -v node_modules
```
リポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で MediaWiki を grep し、稼働しているサービス・バージョンを把握する。
2
Post-deployment verification verify
```
Confirm patched version is live in production
```
パッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。

References

advisory phabricator.wikimedia.org
patch gerrit.wikimedia.org