CVE-2021-36128Network attack vector

Global account suppression failure via cross-wiki autoblock mismatch

Published Jul 2, 2021 · Updated Aug 4, 2024

Improper exception handling in MediaWiki CentralAuth through 1.36 causes global account suppression to fail when it issues an autoblock. CentralAuthUser creates cross-wiki suppression blocks with an autoblock target bound to the wrong database domain, so ActorStore rejects the insertion with an InvalidArgumentException. The failure occurs when an authorized operator suppresses a global account; the target account can remain unlocked and visible, while its associated IP address is not automatically blocked.

CVSS severity9.8
Critical
EPSS probability1.50%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper exception handling in MediaWiki CentralAuth through 1.36 causes global account suppression to fail when it issues an autoblock. CentralAuthUser creates cross-wiki suppression blocks with an autoblock target bound to the wrong database domain, so ActorStore rejects the insertion with an InvalidArgumentException. The failure occurs when an authorized operator suppresses a global account; the target account can remain unlocked and visible, while its associated IP address is not automatically blocked.

The record

CVE
CVE-2021-36128
Published
Jul 2, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-755
Attack vector
network
Privileges
Unavailable

Timeline

How it unfolded

  1. Jul 2, 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 privilegesUnavailable in this record.

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.5NIST NVDAV:N/AC:L/Au:N/C:P/I:P/A:P
9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

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
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-755Improper Handling of Exceptional Conditions

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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