JLine is a Java library for handling console input. From 3.0.0 until 3.30.15 and 4.3.1, DefaultHistory.matchPatterns(String patterns, String line) in reader/src/main/java/org/jline/reader/impl/history/DefaultHistory.java converts the HISTORY_IGNORE configuration value into a Java regular expression while escaping only part of its syntax, allowing other regex metacharacters to reach the backtracking engine. An attacker who can control application or user configuration can supply a nested-quantifier expression that is reevaluated whenever a command is added to history, consuming excessive CPU and indefinitely blocking the reader thread. This issue is fixed in versions 3.30.15 and 4.3.1.
History

Tue, 29 Sep 2026 02:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Sun, 27 Sep 2026 12:15:00 +0000

Type Values Removed Values Added
First Time appeared Jline
Jline jline
Vendors & Products Jline
Jline jline

Thu, 24 Sep 2026 12:15:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

threat_severity

Moderate


Wed, 23 Sep 2026 18:30:00 +0000

Type Values Removed Values Added
Description JLine is a Java library for handling console input. From 3.0.0 until 3.30.15 and 4.3.1, DefaultHistory.matchPatterns(String patterns, String line) in reader/src/main/java/org/jline/reader/impl/history/DefaultHistory.java converts the HISTORY_IGNORE configuration value into a Java regular expression while escaping only part of its syntax, allowing other regex metacharacters to reach the backtracking engine. An attacker who can control application or user configuration can supply a nested-quantifier expression that is reevaluated whenever a command is added to history, consuming excessive CPU and indefinitely blocking the reader thread. This issue is fixed in versions 3.30.15 and 4.3.1.
Title JLine: ReDoS via `HISTORY_IGNORE` Configuration Variable
Weaknesses CWE-1333
References
Metrics cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published: 2026-09-23T18:11:25.998Z

Updated: 2026-09-29T02:05:26.410Z

Reserved: 2026-08-20T19:59:59.603Z

Link: CVE-2026-77420

cve-icon Vulnrichment

Updated: 2026-09-29T02:05:20.786Z

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-09-23T19:19:15.510

Modified: 2026-09-30T19:38:27.293

Link: CVE-2026-77420

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-09-23T18:11:25Z

Links: CVE-2026-77420 - Bugzilla