Inefficient regular expression complexity in jline3 - CVE-2026-77422
Published: September 9, 2026
Vulnerability identifier: #VU148441
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-2026-77422
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 built-in grep command\'s pattern handling when processing a crafted regular expression against non-matching input. A remote attacker can submit a regular expression that causes catastrophic backtracking to cause a denial of service.
Exploitation can cause the command thread to consume high CPU and stop responding.
Affected software
jline3
How to mitigate CVE-2026-77422
Install security update from vendor's website.
jline3 - addressed in versions 3.30.15, 4.3.1