CVE-2021-36125Public exploitNetwork attack vector

Service interruption via unbounded username suggestion loop

Published Jul 2, 2021 · Updated Aug 4, 2024

Denial of service in MediaWiki CentralAuth through 1.36 allows remote authenticated users to exhaust a worker via GlobalRenameRequest. Special:GlobalRenameRequest repeatedly appends three random digits to an overlong current username and retries validation without an exit bound. An account name at least three characters below MaxNameChars makes every candidate invalid, consuming a CPU core until request timeout; concurrent requests can interrupt service.

CVSS severity7.5
High
EPSS probability1.04%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in MediaWiki CentralAuth through 1.36 allows remote authenticated users to exhaust a worker via GlobalRenameRequest. Special:GlobalRenameRequest repeatedly appends three random digits to an overlong current username and retries validation without an exit bound. An account name at least three characters below MaxNameChars makes every candidate invalid, consuming a CPU core until request timeout; concurrent requests can interrupt service.

The record

CVE
CVE-2021-36125
Published
Jul 2, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-835, T1499.003
Attack vector
network
Privileges
authenticated

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

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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 exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-835Loop with Unreachable Exit Condition ('Infinite Loop')
T1499.003Endpoint Denial of Service: Application Exhaustion Flood

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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