Inefficient regular expression complexity in jline3 - CVE-2026-77423
Published: September 9, 2026
Vulnerability identifier: #VU148442
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-2026-77423
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 the JLine3 built-in less viewer\'s Less.getPattern() method when processing user-supplied search patterns. A remote attacker can submit a regular expression with nested quantifiers to cause a denial of service.
The compiled pattern is repeatedly applied against file content and can cause catastrophic backtracking.
Affected software
jline3
How to mitigate CVE-2026-77423
Install security update from vendor's website.
jline3 - addressed in versions 3.30.15, 4.3.1