CVE-2026-75834
MEDIUM
MEDIUM
Priority: 0.01
BB Relevance:
50/100
Published: 2026-08-18
Modified: 2026-10-22
First seen: 2026-10-29
Status: active
Attack Surface
Network
Low Complexity
CVSS Vector Breakdown
AV:
Network
AC:
Low
PR:
Low
UI:
Passive
S:
X
AT:
None
VC:
None
VI:
None
VA:
None
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.