Bug 2539790

Summary: CVE-2026-77422 jline: JLine: Denial of Service via regular expression processing in built-in grep command [fedora-all]
Product: [Fedora] Fedora Reporter: Patrick Del Bello <pdelbell>
Component: jlineAssignee: Marián Konček <mkoncek>
Status: NEW --- QA Contact: Fedora Extras Quality Assurance <extras-qa>
Severity: high Docs Contact:
Priority: high    
Version: rawhideCC: dsupriadi, mizdebsk, mkoncek
Target Milestone: ---Keywords: Security, SecurityTracking
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Hardware: Unspecified   
OS: Unspecified   
Whiteboard: {"flaws": ["4a9c8c21-80e5-4a4b-b301-9bf5f7570f38"]}
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
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Bug Depends On:    
Bug Blocks: 2539620    

Description Patrick Del Bello 2026-09-23 20:57:00 UTC 
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.

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.