CVE-2026-11430Grav CMS Scheduler Webhook Authentication Bypass via Null Short-Circuit

Official description

Grav CMS's scheduler-webhook plugin contains an authentication bypass in the webhook token check. When the webhook feature is enabled but no webhookToken is configured, a compound conditional short-circuits and skips token validation, so an unauthenticated remote attacker who can reach POST /scheduler/webhook can trigger the operator's already-configured scheduled jobs by sending a single request. The primitive is triggering-existing-jobs, not attacker-chosen command execution: the attacker controls when the jobs run and which one runs (via ?job=), but does not control what the jobs do. Code execution follows only when the operator has configured a job that shells out, and even then the attacker controls timing rather than payload. Not a default-install issue: reaching the endpoint requires the separate scheduler-webhook GPM plugin to be installed, scheduler.modern.webhook.enabled to be true (default false), and no webhookToken to be configured; a stock Grav or Grav-Admin install exposes nothing here.

Affected products (as reported)

References

• GitHub Security Advisory technical-description
• Product Repository product
• Patch Commit patch
• https://www.vulncheck.com/advisories/grav-cms-scheduler-webhook-authentication-bypass-via-null-short-circuit third-party-advisory