CVE-2021-31547Network attack vector

Authenticated information disclosure via crafted rule iteration

Published Apr 22, 2021 · Updated Aug 3, 2024

Information disclosure in MediaWiki AbuseFilter through 1.35.2 allows remote authenticated users to reveal suppressed edits and usernames. AbuseFilterCheckMatch evaluates crafted rules against suppressed entries and returns match results without enforcing the entries' visibility restrictions. Any account able to invoke the API can iteratively infer protected values, with no reported ability to modify them.

CVSS severity4.3
Medium
EPSS probability0.87%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Information disclosure in MediaWiki AbuseFilter through 1.35.2 allows remote authenticated users to reveal suppressed edits and usernames. AbuseFilterCheckMatch evaluates crafted rules against suppressed entries and returns match results without enforcing the entries' visibility restrictions. Any account able to invoke the API can iteratively infer protected values, with no reported ability to modify them.

The record

CVE
CVE-2021-31547
Published
Apr 22, 2021
Updated
Aug 3, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-200
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 22, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 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 privilegesauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

4.3NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
4.0NIST NVDAV:N/AC:L/Au:S/C:P/I:N/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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-200Exposure of Sensitive Information to an Unauthorized Actor

Public exploit references

No public exploit references are available in this record.

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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