Vulnerability in Jline Jline3

CVE-2026-77422

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.

Vulnerability class: ReDoS (Regular Expression Denial of Service)

Published · last modified .

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.006 (48.5th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 48th percentile — 48.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-77422: held from 0.005 to 0.006.

EPSS over last 30 days · oldest: 0.005 · newest: 0.006 · change: +0.001

Affected products

  • Jline Jline3 — versions >= 3.0.0, < 3.30.15, >= 4.0.0, < 4.3.1

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-77422?
CVE-2026-77422 is a high-severity vulnerability in Jline Jline3, classified under Inefficient Regular Expression Complexity. CVSS score: 7.5/10. Published 2026-09-23.
How severe is CVE-2026-77422?
High severity. CVSS v3 base score is 7.5 out of 10.