CVE-2026-61453 Grav before 2.0.1 XSS via Twig String Concatenation
Attackers with page-write permissions can execute arbitrary JavaScript in visitors' browsers by bypassing XSS validation via Twig string concatenation.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-61453?
CVE-2026-61453 is a medium-severity cross-site scripting vulnerability in getgrav grav, published on 15 Jul 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official 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.
Weakness: CWE-79
Which versions are affected by CVE-2026-61453?
2 open source packages ship an affected version, including getgrav/grav.
| Package | Affected | Fixed in |
|---|---|---|
getgrav/grav Packagist | From 2.0.0 | 2.0.1 |
getgrav/grav Packagist | From 2.0.0 | 2.0.1 |
How do I fix CVE-2026-61453?
Upgrade getgrav/grav to 2.0.1 or later.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2026-61453 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-61453 exists.
Sources
Also known as CVE-2026-61710, GHSA-2c4f-86xc-cr74.