CVE-2026-77421

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 nano editor's regex search mode passes a user-controlled search term from doSearch(String text) in builtins/src/main/java/org/jline/builtins/Nano.java to Java's backtracking regular expression engine without a timeout or backtracking bound. A nested-quantifier expression evaluated against non-matching buffer content can consume excessive CPU and indefinitely block the editor session thread, and remote multi-user deployments can lose a worker thread for each affected session. This issue is fixed in versions 3.30.15 and 4.3.1.

CVSS 3.1

6.5CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

EPSS

0.4% chance of exploitation in the next 30 days; higher than 37% 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

Packages (OSV)

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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