Document Gallery 4.1 - 5.1.1 - Unauthenticated Document Thumbnail Replacement via Thumber Webhook Signature Bypass

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

No collected risk observation for these identifiers. This does not establish absence of exploitation or a zero probability.

The Document Gallery WordPress plugin through 5.1.1 does not verify the signature on one of its unauthenticated webhook endpoints when no shared secret has been configured, which is the default state, allowing unauthenticated users to replace the thumbnail image the site publishes for any document.

Source published

19 Oct 2026 06:46:16 UTC

Source modified

19 Oct 2026 09:31:21 UTC

Observed here

23 Oct 2026 15:48:27 UTC

Source terms

CVE Program Terms of Use

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: cve-program · CVE Program Terms of Use. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 3.1 · 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N