CVE-2026-0817 | CampaignEvents API missing authorization exposes meeting and chat URLs

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.

Published: 2026-01-09 Last update: 2026-06-17 Assigner: c4f26cc8-17ff-4c99-b5e2-38fc1793eacc Source: c4f26cc8-17ff-4c99-b5e2-38fc1793eacc
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-0817 is rated Low Risk (27/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.25%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-0817

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.03% 0.25% +0.22%
2 2026-01-10 — 0.03% —

Full EPSS history (2 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-0817

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.3 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
 3.9 1.4 134c704f-9b21-4f2e-91b3-4a467353bcc0

Weakness enumeration for CVE-2026-0817

Affected software / configurations for CVE-2026-0817

Vendor Product Version Raw CPE
wikimedia campaignevents 1.39 cpe:2.3:a:wikimedia:campaignevents:1.39:*:*:*:*:mediawiki:*:*
wikimedia campaignevents 1.43 cpe:2.3:a:wikimedia:campaignevents:1.43:*:*:*:*:mediawiki:*:*
wikimedia campaignevents 1.44 cpe:2.3:a:wikimedia:campaignevents:1.44:*:*:*:*:mediawiki:*:*
wikimedia campaignevents 1.45 cpe:2.3:a:wikimedia:campaignevents:1.45:*:*:*:*:mediawiki:*:*

References for CVE-2026-0817

cvelogic Threat Intelligence