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VulnerabilityPublished Updated

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

Affects getgrav/gravSource GCVE Database

0

CVSS 5.4 Medium.

Data as of 18 Sep 2026, 01:26 UTC

CVSS 3.1 base score
5.4Medium
How severe the flaw is on the 0–10 CVSS scale.
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

What to do

Affected software

ProductAffectedFixed in
Packagistgetgrav/gravAffected–Fixed in–

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AI-suggested

Since the advisory is a duplicate and withdrawn, consult the original advisory GHSA-q2j8-x8hf-63ch for official patch or mitigation details. Until patched, restrict page-edit permissions to trusted users and monitor for suspicious content.

Description

Grav versions before 2.0.14 have a stored cross-site scripting (XSS) vulnerability in the Security::detectXss() function. A single invalid UTF-8 byte in page content causes all XSS detection patterns to fail, bypassing the XSS safety check. An authenticated user with page-edit permissions but without the XSS whitelist privilege can exploit this to store malicious JavaScript that executes in visitors' browsers.

References

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