CVE-2026-57852

Grav CMS scheduler-webhook plugin contains an authentication bypass vulnerability that allows unauthenticated remote attackers to trigger configured scheduled jobs by exploiting a short-circuit logic flaw in the webhook token validation. Attackers can send a single unauthenticated POST request to the scheduler webhook endpoint to execute all configured scheduled jobs or target a specific job, causing unintended execution of operator-defined commands under the web server process user.

Grav CMS scheduler-webhook plugin contains an authentication bypass vulnerability that allows unauthenticated remote attackers to trigger configured scheduled jobs by exploiting a short-circuit logic flaw in the webhook token validation. Attackers can send a single unauthenticated POST request to the scheduler webhook endpoint to execute all configured scheduled jobs or target a specific job, causing unintended execution of operator-defined commands under the web server process user.

Grav CMS scheduler-webhook plugin contains an authentication bypass vulnerability that allows unauthenticated remote attackers to trigger configured scheduled jobs by exploiting a short-circuit logic flaw in the webhook token validation. Attackers can send a single unauthenticated POST request to the scheduler webhook endpoint to execute all configured scheduled jobs or target a specific job, causing unintended execution of operator-defined commands under the web server process user.

Grav CMS scheduler-webhook plugin contains an authentication bypass vulnerability that allows unauthenticated remote attackers to trigger configured scheduled jobs by exploiting a short-circuit logic flaw in the webhook token validation. Attackers can send a single unauthenticated POST request to the scheduler webhook endpoint to execute all configured scheduled jobs or target a specific job, causing unintended execution of operator-defined commands under the web server process user.

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.

Grav CMS scheduler-webhook plugin contains an authentication bypass vulnerability that allows unauthenticated remote attackers to trigger configured scheduled jobs by exploiting a short-circuit logic flaw in the webhook token validation. Attackers can send a single unauthenticated POST request to the scheduler webhook endpoint to execute all configured scheduled jobs or target a specific job, causing unintended execution of operator-defined commands under the web server process user.