CVE-2024-47845Public exploitNetwork attack vector

Visitor IP disclosure via stylesheet sanitizer bypass

Published Oct 5, 2024 · Updated Oct 7, 2024

Improper output encoding in MediaWiki CSS Extension allows remote attackers to disclose visitor IP addresses through crafted CSS imports. The extension passes whole stylesheets to Sanitizer::checkCSS, which is intended for style attributes and accepts a quoted @import URL that loads unsanitized remote CSS. Crafted rules must reach content processed by the parser function and a visitor must render the page; confirmed impact is visitor IP-address disclosure.

CVSS severity6.9
Medium
EPSS probability0.41%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper output encoding in MediaWiki CSS Extension allows remote attackers to disclose visitor IP addresses through crafted CSS imports. The extension passes whole stylesheets to Sanitizer::checkCSS, which is intended for style attributes and accepts a quoted @import URL that loads unsanitized remote CSS. Crafted rules must reach content processed by the parser function and a visitor must render the page; confirmed impact is visitor IP-address disclosure.

The record

CVE
CVE-2024-47845
Published
Oct 5, 2024
Updated
Oct 7, 2024
Vendor
Wikimedia Foundation
Product
MediaWiki Extension: CSS
Classifications
CWE-116
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 5, 2024CVE publishedPublication date reported by the CVE source.
  2. Oct 7, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=1.39.0 <1.39.9
  2. Affected versionversion=1.41.0 <1.41.3
  3. Affected versionversion=1.42.0 <1.42.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Wikimedia Foundation · MediaWiki Extension: CSSversion=1.39.0 <1.39.9; version=1.41.0 <1.41.3; version=1.42.0 <1.42.2
Wikimedia Foundation · MediaWiki CSS Extensionversion=1.39.x <1.39.9; version=1.41.x <1.41.3; version=1.42.x <1.42.2

Published CVSS scores

8.2NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:L/A:N
6.9Wikimedia FoundationCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-116Improper Encoding or Escaping of Output

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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