---
title: "CVE-2026-41428: Budibase: Authentication Bypass via Unanchored Regex in Public Endpoint Matcher — Unauthenticated Access to Protected Endpoints"
url: https://erroneo.us/security/cve/CVE-2026-41428/
description: "CVE-2026-41428 (@budibase/backend-core (npm)): Budibase is an open-source low-code platform. Prior to 3.35.4, the authenticated middleware uses unanchored…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-04-24
date_modified: 2026-04-27
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2026-41428"
kev: false
cvss: 9.1
epss: 0.00628
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2026-41428: Budibase: Authentication Bypass via Unanchored Regex in Public Endpoint Matcher — Unauthenticated Access to Protected Endpoints

**Signal:** Critical and remotely reachable. No known exploitation yet, but it is network-reachable without credentials. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- Not in CISA KEV , but CISA’s SSVC assessment records a public proof-of-concept, so attack code exists.
- EPSS 0.6% , percentile 49: FIRST’s model estimates a 0.6% chance of exploitation activity in the next 30 days, higher than 49% of all scored CVEs (low). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Only applies if your dependency tree includes @budibase/backend-core (npm) <= 3.35.3, no fixed version listed . Check your lockfile, including transitive dependencies.

## What it is

Budibase is an open-source low-code platform. Prior to 3.35.4, the authenticated middleware uses unanchored regular expressions to match public (no-auth) endpoint patterns against ctx.request.url. Since ctx.request.url in Koa includes the query string, an attacker can access any protected endpoint by appending a public endpoint path as a query parameter. For example, POST /api/global/users/search?x=/api/system/status bypasses all authentication because the regex /api/system/status/ matches in the query string portion of the URL. This vulnerability is fixed in 3.35.4.

## Affected packages

- npm `@budibase/backend-core` <= 3.35.3 → fixed: none listed

## Affected products (CVE record)

- Budibase budibase: < 3.35.4

## Severity

- GitHub_M CVSS 3.1: 9.1 `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H`
- GitHub CVSS 3.1: 9.1 `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H`

## Exploitation

- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation poc , automatable no , technical impact partial .
- FIRST EPSS (model of 2026-10-21): 0.63% probability of exploitation activity in the next 30 days; percentile 49.

## Sources

- [GitHub Advisory GHSA-8783-3wgf-jggf](https://github.com/advisories/GHSA-8783-3wgf-jggf)
- [CVE.org record CVE-2026-41428](https://www.cve.org/CVERecord?id=CVE-2026-41428)
- [NVD entry CVE-2026-41428](https://nvd.nist.gov/vuln/detail/CVE-2026-41428)
- [github.com](https://github.com/Budibase/budibase/security/advisories/GHSA-8783-3wgf-jggf)

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Source page: https://erroneo.us/security/cve/CVE-2026-41428/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt