CVE-2026-54351: Budibase: Mass Assignment in Webhook Trigger Allows Cross-Workspace Automation Execution via appId Override

Severity: critical (CVSS 9.6 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.5% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2026-06-26 · updated 2026-06-30
Weakness: CWE-915

Description

Budibase is an open-source low-code platform. Prior to 3.39.9, the webhook trigger endpoint in Budibase is publicly accessible and passes the full HTTP request body into automation execution parameters. A mass assignment vulnerability in externalTrigger() allows an attacker to overwrite the internal appId property by including it in the webhook POST body. When the automation is processed asynchronously (the default path for webhooks without a collect step), the worker executes the attacker-defined automation in the context of the victim's workspace, granting full read/write access to the victim's database. This vulnerability is fixed in 3.39.9.

Affected products

budibase: before 3.39.9 — fixed in 3.39.9

How to fix

Upgrade to a fixed version: budibase 3.39.9. Check the vendor advisory for mitigations.

References

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