Inefficient regular expression complexity in linkify-it - CVE-2026-48801
Published: August 31, 2026
Vulnerability identifier: #VU146434
CSH Severity: Medium
CVSS v4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-48801
CWE-ID: CWE-1333
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to inefficient regular expression complexity in LinkifyIt.prototype.match when processing user-supplied text containing many fuzzy links or email-like strings. A remote attacker can send a specially crafted request body to cause a denial of service.
This affects services that synchronously render untrusted Markdown with linkification enabled on the request path, including transitive use through markdown-it with linkify:true.
Affected software
linkify-it
Confluence Data Center
Ansible Automation Platform
Fedora
python-linkify-it-py
Confluence Data Center
Ansible Automation Platform
Fedora
python-linkify-it-py
How to mitigate CVE-2026-48801
Install security update from vendor's website.
linkify-it - update to 5.0.1
Confluence Data Center - addressed in versions 9.2.23, 10.2.15
python-linkify-it-py - update to 2.1.1-1.fc44
Ansible Automation Platform - update to 2.2.0
Confluence Data Center - addressed in versions 9.2.23, 10.2.15
python-linkify-it-py - update to 2.1.1-1.fc44
Ansible Automation Platform - update to 2.2.0