---
title: "CVE-2026-77422: JLine - Denial of Service"
description: "JLine 3.0.0 to 3.30.15 and 4.3.1 contain a denial of service caused by excessive backtracking in user-controlled regular expressions in the built-in grep command, letting remote attackers cause CPU exhaustion, exploit requires remote shell access."
url: https://panop.io/threat-heartbeat/CVE-2026-77422/
---

# CVE-2026-77422 JLine - Denial of Service

JLine 3.0.0 to 3.30.15 and 4.3.1 contain a denial of service caused by excessive backtracking in user-controlled regular expressions in the built-in grep command, letting remote attackers cause CPU exhaustion, exploit requires remote shell access.

CVSS base score 7.5 /10

High

CISA KEV

Not listed

Public exploit

None known

EPSS

0.50% chance of exploitation in 30 days

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-77422)

## Details

Type

Denial of Service

Impact

Denial Of Service

CVSS vector

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

Published

23 September 2026

Updated

15 October 2026

Weakness

[CWE-1333](https://cwe.mitre.org/data/definitions/1333.html)

## Vendor fix

Update to versions 3.30.15 or 4.3.1 or later.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

## References

- [https://nvd.nist.gov/vuln/detail/CVE-2026-77422](https://nvd.nist.gov/vuln/detail/CVE-2026-77422)
- [https://github.com/jline/jline3/commit/1d5fc3099e77938b971e197211cad2d4fbb17541](https://github.com/jline/jline3/commit/1d5fc3099e77938b971e197211cad2d4fbb17541)
- [https://github.com/jline/jline3/commit/341ee69ccc57b7733c1b40d6993219b64b3206ae](https://github.com/jline/jline3/commit/341ee69ccc57b7733c1b40d6993219b64b3206ae)
- [https://github.com/jline/jline3/pull/2012](https://github.com/jline/jline3/pull/2012)
- [https://github.com/jline/jline3/pull/2018](https://github.com/jline/jline3/pull/2018)
- [https://github.com/jline/jline3/releases/tag/4.3.1](https://github.com/jline/jline3/releases/tag/4.3.1)
- [https://github.com/jline/jline3/releases/tag/jline-3.30.15](https://github.com/jline/jline3/releases/tag/jline-3.30.15)
- [https://github.com/jline/jline3/security/advisories/GHSA-r2xf-8xr9-62gw](https://github.com/jline/jline3/security/advisories/GHSA-r2xf-8xr9-62gw)

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## What this record can't tell you

- Whether you run the affected software, and where
- Whether an attacker can actually reach and exploit it
- The misconfigurations that never get a CVE number
- What it would cost the business, ranked into what to fix first

Panop answers these inside your environment, for this CVE and every other finding.

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