vulnerability / NVI-00005543 / Revision 1

Duplicate Advisory: Grav: Single invalid UTF-8 byte disables every rule in Security::detectXss(), bypassing the page-content XSS safety gate

OSV carries this publisher advisory for getgrav/grav. This is an aggregated source copy; consult the original publisher and compare update dates.

source listedwithdrawnGHSA-993v-76jg-67xr

This report has not inspected your inventory, configuration, deployed build, reachability or evidence. A catalog listing and a severity score do not establish exposure or compromise.

01 / Meaning

Why it matters

Published affected context helps an owner decide what evidence to gather. This report has not examined your application.

02 / Applicability

The affected context

Affected versions, configuration prerequisites and known exclusions are public. Confirm each one against the deployed service.

getgrav/grav

source listed

ECOSYSTEM: introduced 0

### Duplicate Advisory This advisory has been withdrawn because it is a duplicate of GHSA-q2j8-x8hf-63ch. This link is maintained to preserve external references. ### Original Description Grav before 2.0.14 contains a stored cross-site scripting vulnerability in the Security::detectXss() function (system/src/Grav/Common/Security.php). All XSS detection patterns use the PCRE /u (UTF-8) modifier, so a single invalid UTF-8 byte anywhere in page content causes preg_match() to return false for every pattern, silently bypassing the save-time XSS safety gate (Validation::checkSafety()). An authenticated attacker with page-edit permissions (without the security.xss_whitelist privilege) can store malicious JavaScript that executes in the browser of a visitor who views the affected page.

GitHub Advisory Database via OSV

03 / Response

What to do next

investigate
Identify the exact component and deployed version, examine the linked publisher’s conditions, and retain evidence of any mitigation.
Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system. GitHub Advisory Database via OSV

A fixed release is not deployment evidence.

Check current vendor support and compatibility. After making a change, verify the deployed build and relevant runtime conditions. Keep the evidence, owner and time. An updated lockfile alone does not prove what is running.

04 / Limits

What this report cannot establish

Customer inventory, deployment, reachability and exploitation have not been inspected.

Read the collection and interpretation limits ↗

05 / Provenance

Sources you can inspect

Each assertion retains its source. Mirrored records may repeat one underlying publisher; additional links are not independent corroboration.

GHSA-993v-76jg-67xr ↗
GitHub Advisory Database via OSV · vendor advisory
Observed Oct 31, 2026. GitHub-origin advisory, CC-BY-4.0; OSV is an aggregate copy, not independent corroboration.

Public revision history

Only published revisions appear here. Routine fetches do not create a material-change event.

Revision 1 · Oct 31, 2026
First indexed by Null; source disclosure date is shown separately.

Read the public revision data ↗