Bug 2539620 (CVE-2026-77422)

Summary:	CVE-2026-77422 org.jline/jline: JLine: Denial of Service via regular expression processing in built-in grep command
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	high	Docs Contact:
Priority:	high
Version:	unspecified	CC:	asyoung, eglynn, gmalinko, janstey, jhollowa, jjoyce, jpretori, jschluet, kaycoth, lhh, mburns, mgarciac, pdelbell, prichard, rstepani, sthirugn
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	---
Doc Text:	A flaw was found in JLine, a Java library for handling console input. The built-in grep command accepts user-controlled regular expressions and automatically wraps them, which can amplify backtracking in the regular expression engine. A remote attacker could exploit this by providing a specially crafted regular expression, leading to excessive CPU consumption and indefinitely blocking a command worker. This can result in a Denial of Service (DoS) for affected systems.	Story Points:	---
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:	2539790
Bug Blocks:

Description OSIDB Bzimport 2026-09-23 18:24:39 UTC

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.