Budibase Universal Auth Bypass via Webhook Query Param Injection

published 2026-03-09 8 mo ago modified 2026-06-17 4 mo ago also EUVD-2026-10358

cvss: 9.1; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 16.7%; EPSS 16.7% chance of exploitation in 30 days, percentile 97%
public exploits: 0; none known, plus a Nuclei check

Budibase is a low code platform for creating internal tools, workflows, and admin panels. In 3.31.4 and earlier, the Budibase server's authorized() middleware that protects every server-side API endpoint can be completely bypassed by appending a webhook path pattern to the query string of any request. The isWebhookEndpoint() function uses an unanchored regex that tests against ctx.request.url, which in Koa includes the full URL with query parameters. When the regex matches, the authorized() middleware immediately calls return next(), skipping all authentication, authorization, role checks, and CSRF protection. This means a completely unauthenticated, remote attacker can access any server-side API endpoint by simply appending ?/webhooks/trigger (or any webhook pattern variant) to the URL.

CISA SSVC

Exploitation: Proof of concept is public
Automatable: yes
Technical impact: total
Assessed: 8 mo ago (2026-03-10)

Exploit prediction

16.68% chance of exploitation in the next 30 days, higher than 97% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

Nuclei template Budibase - Authentication Bypass nuclei detection template
github.com https://github.com/Budibase/budibase/security/advisories/GHSA-gw94-hprh-4wj8 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
CNA	3.1	9.1	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Affected products

Budibase budibase

Classification

Weakness

CWE-74 Improper Neutralization of Special Elements in Output Used by a Downstream Component

References

github.com /Budibase/budibase/security/advisories/GHSA-gw94-hprh-4wj8
exploit, vendor-advisory

Sources

CVE List CVE-2026-31816
NVD CVE-2026-31816

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.

Summary