---
id: GHSA-373m-p57p-8665
title: >-
  Duplicate Advisory: Grav: XSS Blueprint Validation Bypass via Twig String
  Concatenation
summary: >-
  Duplicate Advisory: Grav: XSS Blueprint Validation Bypass via Twig String
  Concatenation
severity: medium
cvss: 6.1
cwe:
  - CWE-79
vendor: getgrav
product: getgrav/grav
ecosystem: composer
affected:
  - getgrav/grav = 2.0.0
published: '2026-07-15'
updated: '2026-09-16'
sourceUpdated: '2026-09-16T22:13:09Z'
source: GHSA
sourceUrl: 'https://github.com/advisories/GHSA-373m-p57p-8665'
references:
  - url: 'https://github.com/getgrav/grav/security/advisories/GHSA-2c4f-86xc-cr74'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-61453'
  - url: >-
      https://www.vulncheck.com/advisories/grav-before-xss-via-twig-string-concatenation
  - url: 'https://github.com/advisories/GHSA-373m-p57p-8665'
tags:
  - ghsa
  - composer
ingestedAt: '2026-09-16T23:07:58.095Z'
---

## Overview

### Duplicate Advisory
This advisory has been withdrawn because it is a duplicate of GHSA-2c4f-86xc-cr74. This link is maintained to preserve external references.

### Original Description
Grav v2.0.0 contains a cross-site scripting vulnerability (fixed in 2.0.1). The XSS blueprint validator (Security::detectXss()) runs on raw page content before Twig processing. When Twig content processing is enabled (twig_content.process_enabled: true), an attacker with page-write API permission can use Twig's string concatenation operator (~) to dynamically construct event handler names, dangerous tag names, or dangerous protocols at render time (e.g. {% set x = "on" ~ "error" %}). The validator sees only the harmless Twig expression and allows the content, but after Twig rendering the output (rendered via {{ page.content|raw }}) contains an active payload such as <img src=1 onerror=alert(1)>, executing arbitrary JavaScript in visitors' browsers.

## Affected packages

- `getgrav/grav = 2.0.0`

## Remediation

Refer to the advisory for the patched release.