No exploitation reportedFix available

CVE-2021-41800

Q: Is CVE-2021-41800 actively exploited?

Active exploitation of CVE-2021-41800 has not been confirmed. Its EPSS score was 1.8% on 2026-10-23, the estimated probability of exploitation in the next 30 days.

Q: What is the CVSS score for CVE-2021-41800?

CVE-2021-41800 has a CVSS v3 base score of 5.3 (MEDIUM severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L.

No exploitation reported by the sources we read.

Published2021-10-11
WeaknessCWE-770

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

MediaWiki before 1.36.2 allows a denial of service (resource consumption because of lengthy query processing time). Visiting Special:Contributions can sometimes result in a long running SQL query because PoolCounter protection is mishandled.

Timeline

dates in UTC

2021-10-1108:15CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 21:37 UTC

Indicators tagged with this CVE, per day0 indicators over 7 days

Block these indicators

Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2021-41800?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2021-41800?format=csv
TAXII collection of exploited CVEs
The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD · OSV

Fedoraproject fedora

Branch	Affected	Fixed in	Source
33.x	= 33	no fix published	NVD
34.x	= 34	no fix published	NVD
35.x	= 35	no fix published	NVD

Mediawiki

Branch	Affected	Fixed in	Source
1.36	< 1.36.2	1.36.2	NVD · OSV

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

Advisories and patches

github.comPatch

Detection

Nuclei template: none so far
Exploit-DB: no entry
Proof-of-concept repositories: none listed

Sources

NVDCVSS 3.15.3read 2026-10-23
NVDCVSS 2.05read 2026-10-23
NVDweakness (CWE)CWE-770read 2026-10-23
FIRST EPSSEPSS score1.8 %2026-10-23
OSVaffected packages—

Technical details

CVSS v3 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Published: 2021-10-11
Last Modified: 2026-06-17
NVD status: Modified

Frequently asked questions

What is CVE-2021-41800?

Is CVE-2021-41800 actively exploited?

Active exploitation of CVE-2021-41800 has not been confirmed. Its EPSS score was 1.8% on 2026-10-23, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2021-41800?

CVE-2021-41800 has a CVSS v3 base score of 5.3 (MEDIUM severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L.

Running mediawiki? Hear about its next vulnerability

Surveillance reads the versions in your stack — a domain, a lockfile or a list — checks each CVE against the ranges its sources publish, and alerts you when one you run is exploited or enters CISA KEV. A version it cannot read stays « version not verified ».

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