budibase up to 3.39.8 Socket Connection toctou

Summaryinfo

A vulnerability, which was classified as critical, was found in budibase up to 3.39.8. This vulnerability affects unknown code of the component Socket Connection Handler. Such manipulation leads to toctou. This vulnerability is uniquely identified as CVE-2026-54353. The attack can be launched remotely. No exploit exists. You should upgrade the affected component.

Detailsinfo

A vulnerability was found in budibase up to 3.39.8 and classified as critical. Affected by this issue is some unknown functionality of the component Socket Connection Handler. The manipulation with an unknown input leads to a toctou vulnerability. Using CWE to declare the problem leads to CWE-367. The product checks the state of a resource before using that resource, but the resource's state can change between the check and the use in a way that invalidates the results of the check. This can cause the product to perform invalid actions when the resource is in an unexpected state. Impacted is confidentiality, integrity, and availability. CVE summarizes:

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.

The advisory is shared for download at github.com. This vulnerability is handled as CVE-2026-54353 since 06/12/2026. The exploitation is known to be easy. The attack may be launched remotely. There are neither technical details nor an exploit publicly available.

Upgrading to version 3.39.9 eliminates this vulnerability.

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Productinfo

Name

• budibase

Version

• 3.39.0
• 3.39.1
• 3.39.2
• 3.39.3
• 3.39.4
• 3.39.5
• 3.39.6
• 3.39.7
• 3.39.8

Website

• Product: https://github.com/Budibase/budibase/

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