CVE-2026-42611 is a high-severity cross-site scripting (XSS) vulnerability in getgrav/grav (composer), affecting versions < 2.0.0-beta.2. It is fixed in 2.0.0-beta.2.
Summary A low-privileged (with the ability to create a page) user can cause XSS with the injection of svg element. The XSS can further be escalated to dump the entire system information available under /admin/config/info whenever a Super Admin visits the page; which can further be chained with the use of admin-nonce to do a complete server compromise (RCE). Details Affected endpoint: admin/pages/<page> Affected code: system/src/Grav/Common/Security.php Specifically the line: assumes that the onevents will always begin with either whitespace, ', " which can easily be bypassed with a simple payload like: <img src=x onload=alert('1')> This XSS Filter practice is broken. Blacklisting every possible scenario that leads to XSS isn't possible. Regex can't parse HTML. It would be better to use an HTMLPurifier. PoC Grav Core + Admin Plugin Grav Version: v1.7.49.5 - Admin v1.10.49.1 Create a low-privileged user with only enough permission to login and perform CRUD on Pages. Login as the low-privileged user and browse to pages: Create a post with the following content: The payload base64 is decoded to: whenever a user with enough privilege visits the attacker-controlled page, a request will be made to the info endpoint and the response will be sent to attacker beacon/listener. Save Start a ncat listener on port 8001. Now as a Super Admin visit the / of Grav http://localhost/grav-admin/ for me: We get a response with the admin-nonce and the entire system information: Impact This is a Stored Cross-Site Scripting (XSS) vulnerability exploitable by a low-privileged user, which leads to exfiltration of the admin session context, including the adminnonce. This nonce can be abused to bypass CSRF protections and authenticate further requests to sensitive admin endpoints. Given Grav’s support for scheduled tasks and extensible plugin architecture, this can be escalated to Remote Code Execution (RCE) under favorable conditions. Affected Component: Grav Core + Admin Plugin (v1.7.49.5 / v1.10.49.1) Impact: Full system compromise via RCE chain originating from low-privilege XSS. CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H Overall CVSS Score: 9.0 High Impact Maintainer note, fix applied (2026-04-24) Fixed in Grav core on the 2.0 branch: commit 5a12f9be8, will ship in 2.0.0-beta.2. Two changes in tandem: Regex bypass (detection layer), the onevents regex that missed unquoted handlers is tightened; see the companion GHSA-9695-8fr9-hw5q advisory for details. Missing dangerous tags, svg, math, option, and select have been added to default security.xssdangeroustags in system/config/security.yaml. svg and math allow inline scripting through their XML namespace and event-handler surface; option/select are the tags attackers use to break out of the admin's select-template context before dropping the payload. Combined with the tightened onevents regex, the PoC <svg>…<script>…</script></svg> (and the GHSA-c2q3 </option></select><img src=x onerror=alert(1)> variant) now trip at least one detector. Files: system/config/security.yaml, dangerous-tags list extended. system/src/Grav/Common/Security.php, regex tightening. tests/unit/Grav/Common/Security/DetectXssTest.php.
Untrusted input is rendered as active markup in a victim's browser, which can run script in their session. Typical impact: session or credential theft, and actions taken as the user.
CVE-2026-42611 has a CVSS score of 8.9 (High). The vector is network-reachable, low privileges required, and user interaction required. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment.
A fixed version is available (2.0.0-beta.2). Upgrading removes the vulnerable code path.
composer
getgrav/grav (< 2.0.0-beta.2)getgrav/grav → 2.0.0-beta.2 (composer)Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter instead of chasing every advisory.
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Upgrade getgrav/grav to 2.0.0-beta.2 or later to resolve this vulnerability.
Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.
CVE-2026-42611 is a high-severity cross-site scripting (XSS) vulnerability in getgrav/grav (composer), affecting versions < 2.0.0-beta.2. It is fixed in 2.0.0-beta.2. Untrusted input is rendered as active markup in a victim's browser, which can run script in their session.
CVE-2026-42611 has a CVSS score of 8.9 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
getgrav/grav (composer) versions < 2.0.0-beta.2 is affected.
Yes. CVE-2026-42611 is fixed in 2.0.0-beta.2. Upgrade to this version or later.
Whether CVE-2026-42611 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
Upgrade getgrav/grav to 2.0.0-beta.2 or later.