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Response snapshot Nov 5, 2026, 23:11 UTC

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VulnerabilityCVE-2026-45061

Budibase vulnerable to SSRF via trivial `.tar.gz` substring bypass in Plugin URL upload (`/api/plugin`)

| Field | Value | |-------|-------| | Title | SSRF via trivial .tar.gz substring bypass in Plugin URL upload | | Product | Budibase (Self-Hosted) | | Version | ≤ 3.34.11 (latest stable as of 2026-03-30) | | Component | packages/server/src/api/controllers/plugin/url.

At a glance

Exploited
Not known
Severity
7.7 High (CVSS 3.1)
Chance of exploitation
Not estimated
Sources
1 source

What to do

GitHub lists first patched versions: budibase: 3.35.10. Confirm the affected range and upgrade guidance in the exact advisory.

Read GitHub-reviewed advisory GHSA-xh5j-727m-w6gg (opens a new tab)

What happened

1. Summary

| Field | Value | |-------|-------| | Title | SSRF via trivial .tar.gz substring bypass in Plugin URL upload | | Product | Budibase (Self-Hosted) | | Version | ≤ 3.34.11 (latest stable as of 2026-03-30) | | Component | packages/server/src/api/controllers/plugin/url.

ts | | Vulnerability Type | CWE-918: Server-Side Request Forgery (SSRF), CWE-184: Incomplete List of Disallowed Inputs | | Severity | High (chained) / Medium (standalone) | | CVSS 3.1 Score (chained) | 7.7 — CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N | | CVSS 3.1 Score (standalone) | 5.4 — CVSS:3.

1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N | | Attack Vector | Network | | Privileges Required | Low (Global Builder role) | | User Interaction | None | | Affected Deployments | All Budibase instances with plugin loading enabled (default) |

Continue reading

---

2. Description

The Plugin URL upload endpoint (POST /api/plugin) validates the submitted URL with a single substring check: url.includes(".tar.gz"). Any URL containing .tar.gz anywhere in the string — in the path, query string, or fragment — passes this check. The URL then proceeds directly to fetchWithBlacklist() with no further validation of host, scheme, or path.

Standalone, this vulnerability is blocked by Budibase's default SSRF blacklist, which covers private IP ranges. But the URL validation layer itself is broken regardless, and it directly enables SSRF in two realistic situations: (1) when chained with the BLACKLIST_IPS bypass ([001]), where the blacklist is empty; and (2) when the plugin server follows HTTP redirects from an external URL to an internal target (the default node-fetch behavior with redirect: 'follow').

The developer team's own test suite (objectStore.spec.ts:393) tests that downloadTarballDirect passes through fetchWithBlacklist — confirming they're aware of the SSRF risk on this path. The .tar.gz substring check as the only URL-level guard was never intended to be the security boundary, but in practice it is.

---

3.1 Trivial substring-based URL validation

File: packages/server/src/api/controllers/plugin/url.ts

// Lines 7-19
export async function urlUpload(url: string, name = "", headers = {}) {
 if (!url.includes(".tar.gz")) {
 // ← ONLY validation: any URL with ".tar.gz" anywhere passes
 throw new Error("Plugin must be compressed into a gzipped tarball.")
 }

 const path = await downloadUnzipTarball(url, name, headers)
 // ↑ url is passed directly — no host allowlist, no scheme check, no path normalization
 try {
 return await getPluginMetadata(path)
 } catch (err) {
 deleteFolderFileSystem(path)
 throw err
 }
}

Problem: url.includes(".tar.gz") checks for a substring anywhere in the full URL string. It does not validate hostname, scheme, or that .tar.gz appears as an actual file extension at the end of the path.

3.2 Bypass examples

| Attack URL | includes(".tar.gz") | Actual request target | |------------|----------------------|----------------------| | http://169.254.169.254/.tar.gz | ✅ passes | AWS IMDS | | http://127.0.0.1:4005/_session.tar.gz | ✅ passes | CouchDB | | http://10.0.0.1:6379/.tar.gz | ✅ passes | Redis | | http://attacker.com/file.tar.gz?x=http://internal/ | ✅ passes | Redirect to internal | | http://internal-host/.tar.gz#fragment | ✅ passes | Internal service |

3.3 Developer awareness of SSRF risk on this path

File: packages/backend-core/src/objectStore/tests/objectStore.spec.ts

// Line 393
it("uses fetchWithBlacklist in downloadTarballDirect", async () => {
 downloadTarballDirect("http://169.254.169.254/metadata/v1/", "tmp")
 // ← team explicitly tests that IMDS is blocked via blacklist
})

The team knows this code path can reach IMDS. They rely on fetchWithBlacklist as the defense — but never tested the .tar.gz substring bypass that trivially routes around it at the URL validation layer.

3.4 Authorization model

| Operation | Endpoint | Required Permission | |-----------|----------|---------------------| | Plugin URL upload | POST /api/plugin | Global Builder |

Key insight: The plugin endpoint is behind globalBuilderRoutes, which requires Global Builder permission. This is a low-privilege role routinely granted to developers on self-hosted instances.

---

4.1 Confidentiality — High (chained) / Low (standalone)

When chained with [001] (BLACKLIST_IPS bypass): - AWS/GCP/Azure IMDS (169.254.169.254) — IAM credentials, service account tokens - CouchDB (127.0.0.1:4005) — application databases, user records - Redis (127.0.0.1:6379) — session tokens - Internal network services (172.16.0.0/12, 10.0.0.0/8)

Standalone (with default blacklist active): - Open redirect chains — if the plugin server follows redirects from external URLs to internal IPs, the blacklist check on the original URL does not protect against the redirected destination. This depends on node-fetch redirect behavior and whether fetchWithBlacklist re-checks the redirected URL.

4.2 Integrity — None (GET-only path)

The plugin URL upload uses GET-only semantics via fetchWithBlacklist. No write operations to internal services via this path.

4.3 Availability — None

No service disruption.

4.4 Scope Change (chained)

Same as [001]: crosses application → infrastructure boundary when combined with the blacklist bypass.

---

5. Proof of Concept

> Verification status: Code-level confirmed. End-to-end Docker test pending. > PoC files are ready: poc/004_plugin_url_ssrf/poc_004_plugin_url_ssrf.py + docker-compose.yml

5.1 Environment Setup

# poc/004_plugin_url_ssrf/docker-compose.yml
services:
 budibase:
 image: budibase/budibase:latest
 environment:
 SELF_HOSTED: "1"
 BLACKLIST_IPS: "" # ← enables chained SSRF (001)
 JWT_SECRET: "poc_jwt_secret"
 BB_ADMIN_USER_EMAIL: "

Affected package ranges reported by GitHub:
budibase: <= 3.34.11

Scores and how they were measured

CVSS base severity

7.7

Version 3.1As of

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N

Measurement source (opens a new tab)

How bad it is if exploited. Not a prediction of exploitation or proof you are exposed.

EPSS probability

Not available

A model's estimate of exploitation in the next 30 days, not certainty or your own risk.

Related technology

Sources

  1. Primary source

    GitHub-reviewed advisory GHSA-xh5j-727m-w6gg (opens a new tab)

    The public advisory supplies the description, affected package/version ranges, and any listed CVSS metric. GitHub review is not local review.

    Published Checked

  2. Primary source

    GitHub public advisory API page (opens a new tab)

    The API page supplied GHSA-xh5j-727m-w6gg, its actual identifiers, source dates, and structured metrics.

    Published Date not suppliedChecked

Cite this record

For factual claims, cite the primary sources above; cite KEVWire for its compilation, dates, and classifications.

APA

KEVWire. (2026, November 5). Budibase vulnerable to SSRF via trivial `.tar.gz` substring bypass in Plugin URL upload (`/api/plugin`) (CVE-2026-45061). https://kevwire.com/record/CVE-2026-45061

MLA

"Budibase vulnerable to SSRF via trivial `.tar.gz` substring bypass in Plugin URL upload (`/api/plugin`) (CVE-2026-45061)." KEVWire, 5 Nov. 2026, kevwire.com/record/CVE-2026-45061.

Chicago

KEVWire. "Budibase vulnerable to SSRF via trivial `.tar.gz` substring bypass in Plugin URL upload (`/api/plugin`) (CVE-2026-45061)." Last modified November 5, 2026. https://kevwire.com/record/CVE-2026-45061.

Evidence summary (plain text)

Budibase vulnerable to SSRF via trivial `.tar.gz` substring bypass in Plugin URL upload (`/api/plugin`) (May 11, 2026).
| Field | Value |
|-------|-------|
| Title | SSRF via trivial .tar.gz substring bypass in Plugin URL upload |
| Product | Budibase (Self-Hosted) |
| Version | ≤ 3.34.11 (latest stable as of 2026-03-30) |
| Component | packages/server/src/api/controllers/plugin/url.ts |
| Vulnerability Type | CWE-918: Server-Side Request Forgery (SSRF), CWE-184: Incomplete List of Disallowed Inputs |
| Severity | High (chained) / Medium (standalone) |
| CVSS 3.1 Score (chained) | 7.7 — CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N |
| CVSS 3.1 Score (standalone) | 5.4 —…
CVSS 7.7 (version 3.1; evidence as of Nov 5, 2026; https://github.com/advisories/GHSA-xh5j-727m-w6gg).
Sources:
GitHub-reviewed advisory GHSA-xh5j-727m-w6gg: https://github.com/advisories/GHSA-xh5j-727m-w6gg
GitHub public advisory API page: https://api.github.com/advisories?type=reviewed&per_page=100&sort=updated&direction=desc
Record ID: CVE-2026-45061.
Record origin: Ingested record.
AI evidence: Not assessed.
Known exploitation: Not assessed.
Zero-day status: Not assessed. KEV membership alone does not establish zero-day status.
About this data

This record was ingested from a data source. Retrieved: Nov 5, 2026, 23:10 UTC. Ingestion is not an independent editorial investigation.

A CISA KEV listing documents known exploitation, not necessarily a zero-day; absence from the catalog does not prove a vulnerability has never been exploited.

Technology tags indicate possible relevance, not verified exposure. Confirm the affected product, version, and configuration against your own inventory; KEVWire does not scan your systems.

A personal reading checklist on this device, not verified remediation.

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