Inefficient regular expression complexity in jline3 - CVE-2026-77420
Published: September 9, 2026
Vulnerability identifier: #VU148439
CSH Severity: Low
CVSS v4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-77420
CWE-ID: CWE-1333
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a local user to cause a denial of service.
The vulnerability exists due to inefficient regular expression complexity in the DefaultHistory.matchPatterns() method when processing a crafted HISTORY_IGNORE configuration value while adding a command line to history. A local user can configure a malicious HISTORY_IGNORE pattern to cause a denial of service.
Applications embedding the jline-reader component are affected only when HISTORY_IGNORE can be configured through user configuration or application settings.
Affected software
jline3
How to mitigate CVE-2026-77420
Install security update from vendor's website.
jline3 - addressed in versions 3.30.15, 4.3.1