EUVD-2026-41009
GHSA-gvg3-mcqq-v953
Severity by source
CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:N/VI:N/VA:N/SC:N/SI:N/SA:N
Admin-only Special:Block page requires PR:H; XSS crosses scope boundary to victim browsers yielding S:C with low C and I impact on affected sessions.
Primary rating from Vendor (wikimedia-foundation).
CVSS VectorVendor: wikimedia-foundation
CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:N/VI:N/VA:N/SC:N/SI:N/SA:N
Lifecycle Timeline
2DescriptionCVE.org
Improper Neutralization of Input During Web Page Generation (XSS or 'Cross-site Scripting') vulnerability in Wikimedia Foundation MediaWiki.
This vulnerability is associated with program files resources/src/mediawiki.Special.Block/SpecialBlock.Vue.
AnalysisAI
Cross-site scripting in MediaWiki's Special:Block Vue.js component allows a high-privileged user - such as a wiki administrator - to inject malicious scripts that execute in the browsers of other users who subsequently view the affected block interface output. The vulnerability is isolated to the SpecialBlock.Vue frontend component, gating exploitation behind administrative access. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Exploitation requires the attacker to already hold high-privileged (administrator or equivalent) access to the MediaWiki installation - specifically, rights to use Special:Block. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The CVSS 4.0 vector (AV:N/AC:L/AT:N/PR:H/UI:P) confirms network exploitability with low complexity but mandates high attacker privileges and passive victim user interaction - PR:H strongly constrains the realistic attacker pool to wiki administrators or similarly privileged accounts. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | An attacker who holds wiki administrator credentials navigates to Special:Block and submits a block action containing a crafted XSS payload embedded in a user-input field that is rendered unsanitized by `SpecialBlock.Vue`. When a second administrator or privileged user views the resulting block confirmation or block log entry, the injected script executes in their browser, potentially exfiltrating session tokens or performing privileged actions on their behalf. … |
| Remediation | No vendor-released patch has been identified at time of analysis - affected version range is based solely on a wildcard CPE with no confirmed fix version. … Detailed patch versions, workarounds, and compensating controls in full report. |
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Same weakness CWE-79 – Cross-site Scripting (XSS)
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External POC / Exploit Code
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