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.
Published: 2026-08-18
Score: 5.1 Medium
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

No vendor fix or workaround currently provided.

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Tracking

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Advisories

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History

Tue, 18 Aug 2026 11:30:00 +0000

Type Values Removed Values Added
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.
Title Grav before 2.0.14 Stored XSS via Invalid UTF-8 Byte
First Time appeared Getgrav
Getgrav grav
Weaknesses CWE-79
CPEs cpe:2.3:a:getgrav:grav:*:*:*:*:*:*:*:*
Vendors & Products Getgrav
Getgrav grav
References
Metrics cvssV3_1

{'score': 5.4, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N'}

cvssV4_0

{'score': 5.1, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N'}

Subscriptions

Getgrav Grav
cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published:

Updated: 2026-08-18T11:19:45.094Z

Reserved: 2026-08-18T10:57:39.580Z

Link: CVE-2026-75834

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-08-18T12:19:33.513

Modified: 2026-08-18T12:19:33.513

Link: CVE-2026-75834

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-08-18T12:30:04Z

Weaknesses
  • CWE-79

    Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')