Inefficient Algorithmic Complexity in linkify-it - CVE-2026-59887
Published: August 31, 2026
Vulnerability identifier: #VU146433
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-2026-59887
CWE-ID: CWE-407
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 algorithmic complexity in the mailto: schema validator scan loop when processing user-supplied text containing repeated mailto: sequences. A remote attacker can send specially crafted input to cause a denial of service.
The issue is reachable through the documented .test() and .match() API and through markdown rendering with linkification enabled.
Affected software
linkify-it
Confluence Data Center
Fedora
python-linkify-it-py
Confluence Data Center
Fedora
python-linkify-it-py
How to mitigate CVE-2026-59887
Install security update from vendor's website.
linkify-it - update to 5.0.2
Confluence Data Center - addressed in versions 9.2.23, 10.2.15
python-linkify-it-py - update to 2.1.1-1.fc44
Confluence Data Center - addressed in versions 9.2.23, 10.2.15
python-linkify-it-py - update to 2.1.1-1.fc44