CVE-2026-58517 Blocked users can create and edit WikiLambda objects

What is CVE-2026-58517?

CVE-2026-58517 is a medium-severity authentication bypass vulnerability in Mediawiki Mediawiki, published on 1 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

Improper neutralization of input terminators vulnerability in The Wikimedia Foundation Mediawiki - WikiLambda Extension allows Authentication Bypass.

This issue affects Mediawiki - WikiLambda Extension: from * before 1.43.9,1.44.6,1.45.4.

Weakness: CWE-288

Which versions are affected by CVE-2026-58517?

It affects 1 product.

Products include Mediawiki Mediawiki.

How do I fix CVE-2026-58517?

Upgrade to a fixed version.

Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.

Is CVE-2026-58517 being exploited?

There is no known exploitation of CVE-2026-58517 in the wild and no public exploit code.

Other vulnerabilities in Mediawiki Mediawiki

• CVE-2023-37303 Denial of service in n/a Critical 9.8
• CVE-2022-29904 SQL injection in n/a Critical 9.8
• CVE-2022-29906 Missing authorization in n/a Critical 9.8
• CVE-2022-28205 Business logic in n/a Critical 9.8
• CVE-2022-28206 Missing authorization in n/a Critical 9.8

All Mediawiki Mediawiki vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as GHSA-9r5v-wvvq-6v9f, MINI-7pw5-hmpg-cxmv, MINI-fr94-qvjf-w233, MINI-frw8-8mjq-hmqj.