5.3

CVE-2026-0817: wikimedia foundation mediawiki - campaignevents extension Missing Authorization

CVSS: 5.3v3.1MediumAnalyzed
Published 09-01-2026Last modified 09-01-2026
Open JSON

Vulnerability summary

CVE-2026-0817 is a medium (CVSS 5.3) Missing Authorization vulnerability in wikimedia foundation mediawiki - campaignevents extension. EPSS estimates a 0.27% chance of exploitation in the next 30 days, higher than 18.4% of scored vulnerabilities.

Overall risk
21/100
0100
Low · default modelHow is this calculated?
CVSS score
5.3/10
010
Medium · v3.1 (CVE.org)
EPSS score
0.27%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Timeline

  1. 09-01-2026
    PublishedVulnerability first disclosed.
  2. 09-01-2026
    Last modifiedVulnerability information updated.

Description

Missing Authorization vulnerability in Wikimedia Foundation MediaWiki - CampaignEvents extension allows Privilege Abuse.This issue affects MediaWiki - CampaignEvents extension: 1.45, 1.44, 1.43, 1.39.

CVSS metrics

2 scores · 2 sources · 1 version

EPSS trend

Probability

0.27%

Chance of exploitation in the next 30 days

Percentile

18%

Versus all other CVEs

30-day change

0.00 pp

From 0.28% on 21-09-2026

21-09-202621-10-2026
EPSS score
0.27%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Wikimedia1 product
Wikimedia foundation1 product

2 vendors · 2 products

References

2 links