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[ CVE-2026-77422 · Published 23 Sep 2026 ]

JLine: ReDoS in Built-in grep Command Amplified by Automatic `.*` Wrapping

CVSS 7.5 EPSS <1%Fix available

[ Why it matters ]Priority signals

  • Public proof-of-concept exploit exists (CISA SSVC)

[ Description ]Official 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 grep command in builtins/src/main/java/org/jline/builtins/PosixCommands.java accepts a user-controlled regular expression in grep(...) and, unless line-regexp mode is used, automatically adds a dot-star prefix and suffix before compiling it with Java's backtracking regular expression engine. The wrapping expands the backtracking search space, so a short nested-quantifier expression evaluated against non-matching input can consume excessive CPU and indefinitely block a command worker, including in remotely exposed shell sessions. This issue is fixed in versions 3.30.15 and 4.3.1.

[ Fixes ]Fixes and patches

  • org.jline:jline-builtins 4.3.1Fixed version · GitHub Advisories · maven package org.jline:jline-builtins: upgrade to 4.3.1 or later (affected >= 4.0.0, < 4.3.1)
  • org.jline:jline-builtins 3.30.15Fixed version · GitHub Advisories · maven package org.jline:jline-builtins: upgrade to 3.30.15 or later (affected >= 3.0.0, < 3.30.15)

[ Packages ]Affected open-source packages

  • org.jline:jline-builtins mavenAffected >= 4.0.0, < 4.3.1 · fixed in 4.3.1 · GHSA-r2xf-8xr9-62gw
  • org.jline:jline-builtins mavenAffected >= 3.0.0, < 3.30.15 · fixed in 3.30.15 · GHSA-r2xf-8xr9-62gw

[ References ]References