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Fencer Intel
high 8.5

CVE-2026-64851 json

Grav Shortcode Core Plugin: Stored XSS in shortcode-core attribute handlers

published 4mo ago modified 2mo ago also EUVD-2026-62548 , GHSA-q5fw-vpqc-fgph

Unreviewed: the maintainers' own advisory

Published by the maintainers on their GitHub repository getgrav/grav. GitHub has not reviewed it into the GitHub Advisory Database, so the affected packages and versions are the maintainers' word. Read the full advisory on GitHub.

cvss
8.5
version 4.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 40%
public exploits
0
none known

Summary

Grav Shortcode Core Plugin allows for the development shortcode plugins that utilize the common format utilized by WordPress and BBCode. Prior to 6.2.2, Grav Shortcode Core passes shortcode syntax through Security::detectXss() because it contains no literal less-than character, then ColorShortcode.php and related attribute handlers concatenate an attacker-controlled parameter into HTML without encoding. An account with admin.pages permission can close the generated attribute and add an event handler, creating stored cross-site scripting that executes for visitors or administrators who view the page. This issue is fixed in version 6.2.2.

Patch / fix

  • getgrav grav 6.2.2

Is CVE-2026-64851 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
total
Assessed
2mo ago

Exploit prediction

0.46% chance of exploitation in the next 30 days, higher than 40% of all scored CVEs (FIRST EPSS, 2026-11-11).

Exploits and checks

  • github.com https://github.com/getgrav/grav/security/advisories/GHSA-q5fw-vpqc-fgph referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 4.0 8.5 CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
CNA 4.0 8.5 CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affected products

  • getgrav grav-plugin-shortcode-core

Classification

Weakness
  • CWE-79 Improper Neutralization of Input During Web Page Generation

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

The maintainers of getgrav/grav published their own advisory on GitHub. Reviewed sources take precedence over it.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.