CVE-2021-35197Known exploitationPublic exploitNetwork attack vector

Unauthorized page purges via ignored sitewide bot blocks

Published Jul 2, 2021 · Updated Aug 4, 2024

Incorrect authorization in MediaWiki allows remote authenticated users with sitewide-blocked bot accounts to purge pages through the Action API. MediaWiki does not apply the sitewide block when Action API purge requests are authorized, so the blocked bot's requests invalidate page caches. Affected releases are before 1.31.15, 1.32.0 through 1.35.2, and 1.36.0; exploitation requires a blocked bot account and alters cached page state.

CVSS severity7.5
High
EPSS probability1.94%
Next 30 days · Sep 16, 2026
Known exploitationReported
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Incorrect authorization in MediaWiki allows remote authenticated users with sitewide-blocked bot accounts to purge pages through the Action API. MediaWiki does not apply the sitewide block when Action API purge requests are authorized, so the blocked bot's requests invalidate page caches. Affected releases are before 1.31.15, 1.32.0 through 1.35.2, and 1.36.0; exploitation requires a blocked bot account and alters cached page state.

The record

CVE
CVE-2021-35197
Published
Jul 2, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-863, T1499.004
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 15, 2021Exploitation reportedWikimedia Commons purge-request service incident
  2. Jul 2, 2021CVE publishedPublication date reported by the CVE source.
  3. 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 privilegesauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

5.0NIST NVDAV:N/AC:L/Au:N/C:N/I:P/A:N
7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/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.

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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 exploitationReported
Public exploitPublished

Weakness, pattern, technique

CWE-863Incorrect Authorization
T1499.004Application or System Exploitation Flood

Public exploit references

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

Reported exploitation

Technologies

Your stack

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Your stack

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