CVE-2026-77421mediumCWE-1333

CVE-2026-77421: medium-severity vulnerability in jline3

JLine: ReDoS in Nano Editor Regex Search Mode

Published

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13Vexday Risk Score

No sign of exploitation. No public exploitation artifact known so far.

ssvc Trackcvss 6.5epss 0.4%
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.
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Affected products
jline · jline3
Related CVEs — jline3

In the same product, most dangerous first.

CVE-2026-77422HIGHJLine: ReDoS in Built-in grep Command Amplified by Automatic `.*` WrappingEPSS 0.6%CVE-2026-56741HIGHJLine: Unauthenticated Remote DoS via Unbounded Telnet NAWS Terminal GeometryEPSS 0.6%CVE-2026-56740HIGHJLine: Unauthenticated Remote Memory Exhaustion via Unbounded Telnet NEW-ENVIRON VariablesEPSS 0.6%CVE-2026-77423HIGHJLine: ReDoS in Built-in Less Viewer SearchEPSS 0.5%CVE-2026-77420MEDIUMJLine: ReDoS via `HISTORY_IGNORE` Configuration VariableEPSS 0.2%