CVE-2026-77422
HIGHDescription
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.
How to fix
No published remediation has been found for this vulnerability's affected products yet.
Mitigation guidance may be in the linked vendor advisories in the References section below.
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CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Exploit Intelligence
Moderate risk: more likely to be exploited than 41% of all known CVEs.
References
Related Vulnerabilities
Other CWE-1333 vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2023-3364 | High | 7.5 | 44% | - | Fix |
| CVE-2024-8124 | High | 7.5 | 40% | - | Fix |
| CVE-2024-25126 | Medium | 5.3 | 35% | - | Fix |
| CVE-2024-2651 | Medium | 6.5 | 33% | - | Fix |
| CVE-2021-32837 | High | 7.5 | 29% | - | Fix |
| CVE-2024-2829 | High | 7.5 | 26% | - | Fix |
Common questions
How do I fix CVE-2026-77422?
No published fix for CVE-2026-77422 has been found yet. Check the linked vendor advisories for guidance as it becomes available.
Is CVE-2026-77422 being actively exploited?
Not that we know of. CVE-2026-77422 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.50% is the estimated probability that it will be exploited in the next 30 days. That is higher than 41% of all scored CVEs.
How severe is CVE-2026-77422?
CVE-2026-77422 has a CVSS v3 base score of 7.5, rated high. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-09-30.