JLine is a Java library for handling console input. From 3.0.0 until 3.30.15 and 4.3.1, the JLine built-in nano editor's regex search mode passes a user-controlled search term from doSearch(String text) in builtins/src/main/java/org/jline/builtins/Nano.java to Java's backtracking regular expression engine without a timeout or backtracking bound. A nested-quantifier expression evaluated against non-matching buffer content can consume excessive CPU and indefinitely block the editor session thread, and remote multi-user deployments can lose a worker thread for each affected session. This issue is fixed in versions 3.30.15 and 4.3.1.

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Advisories
Source ID Title
Github GHSA Github GHSA GHSA-ph9c-7hw9-vhhw JLine: ReDoS in Nano Editor Regex Search Mode
Fixes

Solution

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Workaround

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History

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, the JLine built-in nano editor's regex search mode passes a user-controlled search term from doSearch(String text) in builtins/src/main/java/org/jline/builtins/Nano.java to Java's backtracking regular expression engine without a timeout or backtracking bound. A nested-quantifier expression evaluated against non-matching buffer content can consume excessive CPU and indefinitely block the editor session thread, and remote multi-user deployments can lose a worker thread for each affected session. This issue is fixed in versions 3.30.15 and 4.3.1.
Title JLine: ReDoS in Nano Editor Regex Search Mode
Weaknesses CWE-1333
References
Metrics cvssV3_1

{'score': 6.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-09-23T19:43:56.607Z

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

Link: CVE-2026-77421

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-09-23T19:19:15.700

Modified: 2026-09-23T19:19:15.700

Link: CVE-2026-77421

cve-icon Redhat

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cve-icon OpenCVE Enrichment

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Weaknesses