CVE-2026-77420

MEDIUM 5.5

JLine: ReDoS via `HISTORY_IGNORE` Configuration Variable

CVSS Score

5.5

EPSS Score

0.0%

EPSS Percentile

0th

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.

CWE	CWE-1333
Vendor	jline
Product	jline3
Published	Sep 23, 2026

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CVSS v3 Breakdown

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Attack Vector

Local

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Affected Versions

jline / jline3

>= 3.0.0, < 3.30.15 >= 4.0.0, < 4.3.1

References

NVD ↗ CVE.org ↗ EPSS Data ↗

github.com: https://github.com/jline/jline3/security/advisories/GHSA-5q95-hrpc-m3w3 github.com: https://github.com/jline/jline3/pull/2012 github.com: https://github.com/jline/jline3/pull/2018 github.com: https://github.com/jline/jline3/commit/1d5fc3099e77938b971e197211cad2d4fbb17541 github.com: https://github.com/jline/jline3/commit/341ee69ccc57b7733c1b40d6993219b64b3206ae github.com: https://github.com/jline/jline3/releases/tag/4.3.1 github.com: https://github.com/jline/jline3/releases/tag/jline-3.30.15