CVE-2021-45474Public exploitNetwork attack vector

Script execution via unescaped clientUrl parameter

Published Dec 24, 2021 · Updated Aug 4, 2024

Reflected XSS in MediaWiki FileImporter through 1.37 allows remote attackers to execute script via the clientUrl parameter. Special:ImportFile places the unescaped query value into an error response, causing an appended HTML payload to be interpreted by the browser. Exploitation requires an upload-capable signed-in user to follow the crafted URL, after which script executes in that user's wiki origin.

CVSS severity6.1
Medium
EPSS probability0.97%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Reflected XSS in MediaWiki FileImporter through 1.37 allows remote attackers to execute script via the clientUrl parameter. Special:ImportFile places the unescaped query value into an error response, causing an appended HTML payload to be interpreted by the browser. Exploitation requires an upload-capable signed-in user to follow the crafted URL, after which script executes in that user's wiki origin.

The record

CVE
CVE-2021-45474
Published
Dec 24, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-79, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Dec 24, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

4.3NIST NVDAV:N/AC:M/Au:N/C:N/I:P/A:N
6.1NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1203Exploitation for Client Execution

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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