How severe is CVE-2026-0817?

CVE-2026-0817 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity none, and availability none.

Is CVE-2026-0817 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (16th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-0817?

CVE-2026-0817 primarily affects Wikimedia Campaignevents. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2026-0817?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-0817 have an EU (EUVD) identifier?

Yes. CVE-2026-0817 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-1726.

When was CVE-2026-0817 published?

CVE-2026-0817 was published on 2026-01-09 and last updated on 2026-06-17.

CVE-2026-0817

CVE-2026-0817 is a medium-severity vulnerability in Wikimedia Campaignevents with a CVSS 3.x base score of 5.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-862.

Key facts

Severity: Medium (CVSS 3.x base score 5.3)
EPSS exploit prediction: 0% (16th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-1726
Weakness: CWE-862
Affected product: Wikimedia Campaignevents
Published: 2026-01-09
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2026-0817?: 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.
How severe is CVE-2026-0817?: CVE-2026-0817 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity none, and availability none.
Is CVE-2026-0817 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (16th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-0817?: CVE-2026-0817 primarily affects Wikimedia Campaignevents. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2026-0817?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-0817 have an EU (EUVD) identifier?: Yes. CVE-2026-0817 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-1726.
When was CVE-2026-0817 published?: CVE-2026-0817 was published on 2026-01-09 and last updated on 2026-06-17.

References

Affected products (4)

cpe:2.3:a:wikimedia:campaignevents:1.39:*:*:*:*:mediawiki:*:*
cpe:2.3:a:wikimedia:campaignevents:1.43:*:*:*:*:mediawiki:*:*
cpe:2.3:a:wikimedia:campaignevents:1.44:*:*:*:*:mediawiki:*:*
cpe:2.3:a:wikimedia:campaignevents:1.45:*:*:*:*:mediawiki:*:*

Other CWE-862 (Missing Authorization) vulnerabilities

CVE-2026-0092 — Critical (CVSS 10.0): In Package Manager, there is a possible device lock controller bypass due to a missing permission check. This could…
CVE-2026-33712 — Critical (CVSS 10.0): Typebot is a chatbot builder tool. In versions 3.15.2 and prior, the preview chat endpoint (POST…
CVE-2026-2031 — Critical (CVSS 10.0): An Improper Access Control vulnerability in several internal API endpoints for Google Cloud Application Integration…
CVE-2026-34976 — Critical (CVSS 10.0): Dgraph is an open source distributed GraphQL database. Prior to 25.3.1, the restoreTenant admin mutation is missing…
CVE-2025-30416 — Critical (CVSS 10.0): Sensitive data disclosure and manipulation due to missing authorization. The following products are affected: Acronis…
CVE-2025-45854 — Critical (CVSS 10.0): /server/executeExec of JEHC-BPM 2.0.1 allows attackers to execute arbitrary code via execParams.

Browse all CWE-862 (Missing Authorization) vulnerabilities →