Budibase: Potential SSRF DNS rebinding bypass in outbound fetch validation

published 2026-06-22 4 mo ago modified 2026-08-12 2 mo ago also EUVD-2026-39915 , GHSA-gfq7-5x4g-3xhf

cvss: 8.5; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.2%; EPSS 0.2% chance of exploitation in 30 days, percentile 11%
public exploits: 0; none known

Budibase is an open-source low-code platform. Prior to 3.39.9, authenticated users with automation permissions can bypass Budibase's SSRF blacklist through DNS rebinding. The outbound fetch flow validates a hostname against the blacklist before the request is sent, but the actual socket connection later performs a separate DNS lookup through node-fetch. Since the validated IPs are never pinned to the connection, an attacker-controlled hostname can return a public IP during validation and a private/internal IP during the real connection. This results in a non-blind SSRF primitive against internal services reachable from the Budibase host, including loopback, RFC1918 ranges, and cloud metadata endpoints. This vulnerability is fixed in 3.39.9.

Patch / fix

fixed in 2

npm @budibase/backend-core 3.39.9
budibase budibase 3.39.9

CISA SSVC

Exploitation: Proof of concept is public
Automatable: no
Technical impact: partial
Assessed: 4 mo ago (2026-06-29)

Exploit prediction

0.21% chance of exploitation in the next 30 days, higher than 11% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

github.com https://github.com/Budibase/budibase/security/advisories/GHSA-gfq7-5x4g-3xhf referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
CNA	3.1	8.5	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:N
GitHub	3.1	8.5	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:N
NVD	3.1	7.1	CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:L/A:N

Affected packages

ecosystem	package	affected	fixed in
npm	@budibase/backend-core	<3.39.9	3.39.9

Affected products

Budibase budibase

Classification

Weakness

CWE-367 Time-of-check Time-of-use (TOCTOU) Race Condition
CWE-918 Server-Side Request Forgery

References

github.com /Budibase/budibase/security/advisories/GHSA-gfq7-5x4g-3xhf
exploit, web, vendor-advisory
nvd.nist.gov /vuln/detail/CVE-2026-54353
advisory
github.com /Budibase/budibase
package

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.

Summary