CVE-2026-48147CWE-185CWE-352

Budibase: Unanchored Regex in `matchers.ts` Allows CSRF Bypass via Query String Injection in Budibase Worker

Medium · published May 27, 2026

CVSS v3.1
6.5
EPSS
0%
Percentile
5.7
In the wild
Unconfirmed
What it is

Budibase is an open-source low-code platform. Prior to 3.35.4, the buildMatcherRegex() / matches() functions in packages/backend-core/src/middleware/matchers.ts route patterns are compiled into unanchored regular expressions and tested against ctx.request.url, which includes the full query string. The CSRF middleware in the Budibase Worker uses this matching system to decide whether to skip CSRF token validation. An unauthenticated attacker can forge state-changing cross-origin requests against any Worker API endpoint by injecting a public route pattern into the query string, causing the CSRF middleware to skip token validation entirely. This allows actions such as sending admin invites, modifying global configuration, and managing users without a valid CSRF token. This vulnerability is fixed in 3.35.4.

The record
Technical detail
CVSS v3.1
6.5 · MEDIUM
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N
CVSS v4.0
Not supplied
EPSS
0.00167 · 5.7th percentile
Weaknesses
CWE-185 · Incorrect Regular Expression; CWE-352 · Cross-Site Request Forgery (CSRF)
Published
2026-05-27T17:14Z
EPSS history
Timeline
  • 27 MAY 17:14Z
    Budibase: Unanchored Regex in `matchers.ts` Allows CSRF Bypass via Query String Injection in Budibase Worker
    cvelistv5