What’s Vulnerable › Vulnerabilities

CVE-2026-52766: YesWiki: Unauthenticated arbitrary page deletion via `{{erasespamedcomments}}` action

• Severity: critical (CVSS 9.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.6% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-09-05 · updated 2026-09-09
• Weakness: CWE-276

Description

YesWiki is a wiki system written in PHP. Prior to version 4.6.6, the {{erasespamedcomments}} wiki action (actions/EraseSpamedCommentsAction.php) accepts a suppr[] array from POST and deletes every wiki page whose tag appears in that array, with no authorization check anywhere in the action body or in the page-deletion path it invokes. Combined with YesWiki's allow-by-default action ACL model, any user who has page write access, which is the default for everyone (default_write_acl='*') on a fresh install can permanently delete arbitrary wiki pages, including the front page, admin pages, and pages owned by other users. This issue has been patched in version 4.6.6.

Affected products

• yeswiki: before 4.6.6

References

• https://github.com/YesWiki/yeswiki/commit/ed5b548a705c8091ba0282aaaba73ddda976abef
• https://github.com/YesWiki/yeswiki/releases/tag/v4.6.6
• https://github.com/YesWiki/yeswiki/security/advisories/GHSA-6x7x-gcmf-7r8x
• https://github.com/YesWiki/yeswiki/security/advisories/GHSA-6x7x-gcmf-7r8x

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