CVE-2021-46150Public exploitNetwork attack vector

Browser script execution via unescaped date values

Published Jan 7, 2022 · Updated Aug 4, 2024

MediaWiki CheckUser XSS before 1.35.5, 1.36.x before 1.36.3, and 1.37.x before 1.37.1 lets attackers run browser scripts. LogPager inserts userTimeAndDate, userDate, and userTime output into a raw message through text() without HTML-escaping the date values. Exploitation requires elevated on-wiki privileges to alter a date-related MediaWiki message and a CheckUser user to view Special:CheckUserLog; the script can read or modify data available to that browser session.

CVSS severity4.8
Medium
EPSS probability0.65%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

MediaWiki CheckUser XSS before 1.35.5, 1.36.x before 1.36.3, and 1.37.x before 1.37.1 lets attackers run browser scripts. LogPager inserts userTimeAndDate, userDate, and userTime output into a raw message through text() without HTML-escaping the date values. Exploitation requires elevated on-wiki privileges to alter a date-related MediaWiki message and a CheckUser user to view Special:CheckUserLog; the script can read or modify data available to that browser session.

The record

CVE
CVE-2021-46150
Published
Jan 7, 2022
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-79, T1203
Attack vector
network
Privileges
admin

Timeline

How it unfolded

  1. Jan 7, 2022CVE 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 privilegesadmin

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

4.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N
3.5NIST NVDAV:N/AC:M/Au:S/C:N/I:P/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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesadmin
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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