CVE-2026-75828Public exploitNetwork attack vector

Stored XSS via quote-bypassed event detection

Published Aug 18, 2026 · Updated Aug 18, 2026

Stored XSS in detectXss() in Grav before 2.0.15 allows remote authenticated users to execute script in visitor browsers via page content. In system/src/Grav/Common/Security.php, the on_events regex treats any quote as a quoted-value delimiter, so an unpaired quote inside an unquoted attribute value stops the scan before the following on...= handler and detectXss() returns clean. Editor-level access is required because Validation::checkSafety() is the save-time XSS gate for non-super content, and the stored markup then executes when the page is rendered to visitors.

CVSS severity9.3
Critical
EPSS probability0.34%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored XSS in detectXss() in Grav before 2.0.15 allows remote authenticated users to execute script in visitor browsers via page content. In system/src/Grav/Common/Security.php, the on_events regex treats any quote as a quoted-value delimiter, so an unpaired quote inside an unquoted attribute value stops the scan before the following on...= handler and detectXss() returns clean. Editor-level access is required because Validation::checkSafety() is the save-time XSS gate for non-super content, and the stored markup then executes when the page is rendered to visitors.

The record

CVE
CVE-2026-75828
Published
Aug 18, 2026
Updated
Aug 18, 2026
Vendor
Grav
Product
Grav
Classifications
CWE-79, T1059.007
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 18, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 18, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <2.0.15

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Grav · Gravversion=0 <2.0.15

Published CVSS scores

8.7VulnCheckCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N
9.3VulnCheckCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:H/VI:H/VA:N/SC:H/SI:H/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1059.007JavaScript

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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