YesWiki vulnerable to unauthenticated arbitrary page deletion via {{erasespamedcomments}} action

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

9.1 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H

EPSS

• CVE-2026-52766: 0.58% estimated exploitation activity in the next 30 days; percentile 47.68 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary 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 (defaultwriteacl='') on a fresh install can permanently delete arbitrary wiki pages, including the front page, admin pages, and pages owned by other users. The action's delete() callee is PageManager::deleteOrphaned(), which despite its name does not check whether the target page is orphaned: it issues an unconditional DELETE against pages, links, acls, triples, referrers, and tags tables. Details Three issues compose the vulnerability. 1. actions/EraseSpamedCommentsAction.php performs no authorization check before processing $POST['clean'] / $POST['suppr'][] in…

Published by the source

9 Jul 2026, 20:57 UTC

Last modified by the source

9 Jul 2026, 20:57 UTC

Source last checked

26 Oct 2026, 14:50 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-6x7x-gcmf-7r8x

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# Patch Next advisory brief: CVE-2026-52766

Advisory: YesWiki vulnerable to unauthenticated arbitrary page deletion via `{{erasespamedcomments}}` action
IDs: CVE-2026-52766, GHSA-6x7x-gcmf-7r8x
Record: https://patchnext.com/advisories/cve-2026-52766 (revision 1, source checked 26 Oct 2026, 14:50 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Critical (CVSS 9.1)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: yeswiki/yeswiki 4.6.6. A vendor fix does not mean a deployment is fixed.

## Affected components
- Packagist yeswiki/yeswiki: affected < 4.6.6; fixed in 4.6.6

## Suggested inspection (read-only)
- Packagist yeswiki/yeswiki: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on yeswiki/yeswiki.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-6x7x-gcmf-7r8x (GitHub-reviewed advisory GHSA-6x7x-gcmf-7r8x lists affected ranges: Packagist yeswiki/yeswiki >=0 <4.6.6)

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