CVE-2026-75831Public exploitNetwork attack vector

Stored XSS via unescaped source URL

Published Aug 18, 2026 · Updated Aug 18, 2026

Stored XSS in Grav before 2.0.15 allows remote authenticated users to execute JavaScript in viewers' sessions via crafted Markdown media URLs. AudioMediaTrait and VideoMediaTrait sourceParsedownElement() build a raw HTML source tag and concatenate the media URL fragment into src without escaping, so a double quote in the fragment breaks attribute context and injects live markup such as an auto-firing svg onload payload. Reachability requires page-edit rights or another path to store attacker-controlled Markdown, and impact is bounded to browsers that render the poisoned page, including administrative sessions that view it.

CVSS severity7.6
High
EPSS probability0.31%
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 Grav before 2.0.15 allows remote authenticated users to execute JavaScript in viewers' sessions via crafted Markdown media URLs. AudioMediaTrait and VideoMediaTrait sourceParsedownElement() build a raw HTML source tag and concatenate the media URL fragment into src without escaping, so a double quote in the fragment breaks attribute context and injects live markup such as an auto-firing svg onload payload. Reachability requires page-edit rights or another path to store attacker-controlled Markdown, and impact is bounded to browsers that render the poisoned page, including administrative sessions that view it.

The record

CVE
CVE-2026-75831
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

7.6VulnCheckCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:L/A:N
5.1VulnCheckCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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')
T1059.007Command and Scripting Interpreter: JavaScript

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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