VulnerabilityPublished 11 May 2026Updated 5 Nov 2026

CVE-2026-45061: Budibase vulnerable to SSRF via trivial `.tar.gz` substring bypass in Plugin URL upload (`/api/plugin`)

Affects budibaseSource GCVE Database

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Not known to be exploited · CVSS 7.7 High : upgrade to 3.35.10 soon.

Data as of 5 Nov 2026, 22:34 UTC

CVSS 3.1 base score

7.7High

How severe the flaw is on the 0–10 CVSS scale.

Patch: Available – fixed in 3.35.10

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

Attack Vector: Network
Attack Complexity: Low
Privileges Required: Low
User Interaction: None
Scope: Changed
Confidentiality: High
Integrity: None
Availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: Low: The attacker is authorized with (i.e., requires) privileges that provide basic user capabilities that could normally affect only settings and files owned by a user. Alternatively, an attacker with Low privileges may have the ability to cause an impact only to non-sensitive resources.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Changed: An exploited vulnerability can affect resources beyond the security scope managed by the security authority of the vulnerable component. In this case, the vulnerable component and the impacted component are different and managed by different security authorities.
Confidentiality: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 11 May 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 5 Nov 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade budibase to 3.35.10.

Affected software

Product	Affected	Fixed in
npmbudibase	Affected <3.35.10	Fixed in 3.35.10

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Description

## 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) | --- ## 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. Root Cause Analysis ### 3.1 Trivial substring-based URL validation **File**: `packages/server/src/api/controllers/plugin/url.ts` ```typescript // 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` ```typescript // 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. Impact Analysis ### 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 chec

CWE-918Server-Side Request Forgery (opens in a new tab)
Base weaknessCWE Top 25 (2025): #22OWASP Top 10 A01:2025: Broken Access Control (opens in a new tab)
The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination.
Implementation · Operation
If there is a known list of applications, IP, hostname, and/or domains to which the product is allowed to communicate, then use allowlists to ensure that outgoing requests are restricted to these known entities. The allowlists could be in the application code or possibly enforced by firewalls or network segmentation.
Implementation · Operation
If the product is expected to be able to connect to arbitrary IP addresses or domains, consider using a denylist that includes private network addresses, internal domain names, etc. The denylist could be in the application code or possibly enforced by firewalls or network segmentation.
Implementation · Input Validation
Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
OWASP Cheat Sheets
Server Side Request Forgery Prevention (opens in a new tab)
Unvalidated Redirects and Forwards (opens in a new tab)
Cross Site Scripting Prevention (opens in a new tab)
DOM based XSS Prevention (opens in a new tab)
Authorization (opens in a new tab)
OWASP ASVS 4.0.3
V12.6.1 (opens in a new tab)
V5.2.6 (opens in a new tab)
Attack patterns
Server Side Request Forgery (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

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Description

WeaknessesCWE-918

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