CVE-2026-77423

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.

CVSS 3.1

7.5CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS

0.5% chance of exploitation in the next 30 days; higher than 39% of CVEs (scores of 2026-10-25)

CWE

CWE-1333

Published

2026-09-23

Modified

2026-09-30

Record from

the NVD, synced 2026-10-19

References

• https://github.com/jline/jline3/commit/1d5fc3099e77938b971e197211cad2d4fbb17541
• https://github.com/jline/jline3/commit/341ee69ccc57b7733c1b40d6993219b64b3206ae
• https://github.com/jline/jline3/pull/2012
• https://github.com/jline/jline3/pull/2018
• https://github.com/jline/jline3/releases/tag/4.3.1

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