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Fencer Vulns
critical 9.8

CVE-2019-20041 in the critical feed json

wp_kses_bad_protocol in wp-includes/kses.php in WordPress before 5.3.1 mishandles the HTML5 colon named entity, allowing attackers to bypas…

published 2019-12-27 6 y ago modified 2026-06-17 4 mo ago also EUVD-2019-10597

cvss
9.8
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
4.5%
EPSS 4.5% chance of exploitation in 30 days, percentile 91%
public exploits
0
none known

Summary

wp_kses_bad_protocol in wp-includes/kses.php in WordPress before 5.3.1 mishandles the HTML5 colon named entity, allowing attackers to bypass input sanitization, as demonstrated by the javascript: substring.

Patch / fix

  • wordpress wordpress 5.3.1
  • wordpress Debian 14, Debian 13, Debian 12 5.3.2+dfsg1-1

debian advisories DEBIAN-CVE-2019-20041

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2019-20041 updated cvss 6.5

wordpress: HTML5 colon named entity mishandling in wp_kses_bad_protocol in wp-includes/kses.php allows bypass input sanitization

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

4.53% chance of exploitation in the next 30 days, higher than 91% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 7.5 AV:N/AC:L/Au:N/C:P/I:P/A:P

Classification

Weakness
  • CWE-20 Improper Input Validation
Technology feeds

References

Sources

Fencer Vulns 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.