CVE-2026-77423

Name	CVE-2026-77423
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 less viewer passes user-controlled search and display-filter patterns from getPattern(boolean doDisplayPattern) in builtins/src/main/java/org/jline/builtins/Less.java directly to Java's backtracking regular expression engine and repeatedly applies them to file content. A nested-quantifier expression evaluated against non-matching lines can consume excessive CPU and indefinitely block the session thread, and repeated sessions in Telnet or SSH deployments can exhaust a bounded worker pool. This issue is fixed in versions 3.30.15 and 4.3.1.
Source	CVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
jline (PTS)	forky, sid, bookworm, trixie	1.0-3	fixed
jline2 (PTS)	bookworm	2.14.6-5	fixed
	forky, sid, trixie	2.14.6-6	fixed
jline3 (PTS)	bookworm	3.3.1-3	vulnerable
	trixie	3.3.1-4	vulnerable
	forky, sid	3.3.1-5	vulnerable

The information below is based on the following data on fixed versions.

Package	Type	Release	Fixed Version
jline	source	(unstable)	(not affected)
jline2	source	(unstable)	(not affected)
jline3	source	(unstable)	(unfixed)

Notes

- jline2 <not-affected> (Less pager was introduced in 3.x)
- jline <not-affected> (Less pager was introduced in 3.x)
https://github.com/jline/jline3/security/advisories/GHSA-2v9w-34q6-wpqx
https://github.com/jline/jline3/pull/2018
https://github.com/jline/jline3/commit/341ee69ccc57b7733c1b40d6993219b64b3206ae