UBUNTU-CVE-2026-56741 (CVE-2026-56741)
Vulnerability from osv_ubuntu – Published: 2026-07-17 22:17 – Updated: 2026-07-29 07:59 – Source website
VLAI
Details
JLine is a Java library for handling console input. Prior to 3.30.14, 4.0.16, and 4.2.1, the JLine3 Telnet server remote-telnet module does not apply an upper bound to terminal dimensions received via the Telnet NAWS option, and TelnetIO.handleNAWS() in TelnetIO.java:856-879 reads client-supplied width and height as 16-bit unsigned integers and passes values such as 65535x65535 to setTerminalGeometry(), allowing an unauthenticated remote attacker to repeatedly alternate values and trigger continuous expensive rendering work that causes CPU exhaustion and denial of service. This issue is fixed in versions 3.30.14, 4.0.16, and 4.2.1.
Severity
7.5 (High)
N/A (UNKNOWN)
References
{
"affected": [
{
"ecosystem_specific": {
"binaries": [
{
"binary_name": "libjline-java",
"binary_version": "1.0-2"
}
]
},
"package": {
"ecosystem": "Ubuntu:14.04:LTS",
"name": "jline",
"purl": "pkg:deb/ubuntu/jline@1.0-2?arch=source\u0026distro=trusty"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"1.0-2"
]
},
{
"ecosystem_specific": {
"binaries": [
{
"binary_name": "libjline2-java",
"binary_version": "2.11-2"
}
]
},
"package": {
"ecosystem": "Ubuntu:14.04:LTS",
"name": "jline2",
"purl": "pkg:deb/ubuntu/jline2@2.11-2?arch=source\u0026distro=trusty"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"2.11-1",
"2.11-2"
]
},
{
"ecosystem_specific": {
"binaries": [
{
"binary_name": "libjline-java",
"binary_version": "1.0-2"
}
]
},
"package": {
"ecosystem": "Ubuntu:16.04:LTS",
"name": "jline",
"purl": "pkg:deb/ubuntu/jline@1.0-2?arch=source\u0026distro=xenial"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"1.0-2"
]
},
{
"ecosystem_specific": {
"binaries": [
{
"binary_name": "libjline2-java",
"binary_version": "2.11-4"
}
]
},
"package": {
"ecosystem": "Ubuntu:16.04:LTS",
"name": "jline2",
"purl": "pkg:deb/ubuntu/jline2@2.11-4?arch=source\u0026distro=xenial"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"2.11-4"
]
},
{
"ecosystem_specific": {
"binaries": [
{
"binary_name": "libjline-java",
"binary_version": "1.0-2"
}
]
},
"package": {
"ecosystem": "Ubuntu:18.04:LTS",
"name": "jline",
"purl": "pkg:deb/ubuntu/jline@1.0-2?arch=source\u0026distro=bionic"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"1.0-2"
]
},
{
"ecosystem_specific": {
"binaries": [
{
"binary_name": "libjline2-java",
"binary_version": "2.14.6-1"
}
]
},
"package": {
"ecosystem": "Ubuntu:18.04:LTS",
"name": "jline2",
"purl": "pkg:deb/ubuntu/jline2@2.14.6-1?arch=source\u0026distro=bionic"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"2.11-4",
"2.12.1-1",
"2.14.6-1"
]
},
{
"ecosystem_specific": {
"binaries": [
{
"binary_name": "libjline-java",
"binary_version": "1.0-2"
}
]
},
"package": {
"ecosystem": "Ubuntu:20.04:LTS",
"name": "jline",
"purl": "pkg:deb/ubuntu/jline@1.0-2?arch=source\u0026distro=focal"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"1.0-2"
]
},
{
"ecosystem_specific": {
"binaries": [
{
"binary_name": "libjline2-java",
"binary_version": "2.14.6-3"
}
]
},
"package": {
"ecosystem": "Ubuntu:20.04:LTS",
"name": "jline2",
"purl": "pkg:deb/ubuntu/jline2@2.14.6-3?arch=source\u0026distro=focal"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"2.14.6-3"
]
},
{
"ecosystem_specific": {
"binaries": [
{
"binary_name": "libjline-java",
"binary_version": "1.0-3"
}
]
},
"package": {
"ecosystem": "Ubuntu:22.04:LTS",
"name": "jline",
"purl": "pkg:deb/ubuntu/jline@1.0-3?arch=source\u0026distro=jammy"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"1.0-3"
]
},
{
"ecosystem_specific": {
"binaries": [
{
"binary_name": "libjline2-java",
"binary_version": "2.14.6-4"
}
]
},
"package": {
"ecosystem": "Ubuntu:22.04:LTS",
"name": "jline2",
"purl": "pkg:deb/ubuntu/jline2@2.14.6-4?arch=source\u0026distro=jammy"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"2.14.6-4"
]
},
{
"ecosystem_specific": {
"binaries": [
{
"binary_name": "libjline3-java",
"binary_version": "3.3.1-2"
}
]
},
"package": {
"ecosystem": "Ubuntu:22.04:LTS",
"name": "jline3",
"purl": "pkg:deb/ubuntu/jline3@3.3.1-2?arch=source\u0026distro=jammy"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"3.3.1-2"
]
},
{
"ecosystem_specific": {
"binaries": [
{
"binary_name": "libjline-java",
"binary_version": "1.0-3"
}
]
},
"package": {
"ecosystem": "Ubuntu:24.04:LTS",
"name": "jline",
"purl": "pkg:deb/ubuntu/jline@1.0-3?arch=source\u0026distro=noble"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"1.0-3"
]
},
{
"ecosystem_specific": {
"binaries": [
{
"binary_name": "libjline2-java",
"binary_version": "2.14.6-5"
}
]
},
"package": {
"ecosystem": "Ubuntu:24.04:LTS",
"name": "jline2",
"purl": "pkg:deb/ubuntu/jline2@2.14.6-5?arch=source\u0026distro=noble"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"2.14.6-5"
]
},
{
"ecosystem_specific": {
"binaries": [
{
"binary_name": "libjline3-java",
"binary_version": "3.3.1-3ubuntu1"
}
]
},
"package": {
"ecosystem": "Ubuntu:24.04:LTS",
"name": "jline3",
"purl": "pkg:deb/ubuntu/jline3@3.3.1-3ubuntu1?arch=source\u0026distro=noble"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"3.3.1-3",
"3.3.1-3ubuntu1"
]
},
{
"ecosystem_specific": {
"binaries": [
{
"binary_name": "libjline-java",
"binary_version": "1.0-3build1"
}
]
},
"package": {
"ecosystem": "Ubuntu:26.04:LTS",
"name": "jline",
"purl": "pkg:deb/ubuntu/jline@1.0-3build1?arch=source\u0026distro=resolute"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"1.0-3",
"1.0-3build1"
]
},
{
"ecosystem_specific": {
"binaries": [
{
"binary_name": "libjline2-java",
"binary_version": "2.14.6-6"
}
]
},
"package": {
"ecosystem": "Ubuntu:26.04:LTS",
"name": "jline2",
"purl": "pkg:deb/ubuntu/jline2@2.14.6-6?arch=source\u0026distro=resolute"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"2.14.6-6"
]
},
{
"ecosystem_specific": {
"binaries": [
{
"binary_name": "libjline3-java",
"binary_version": "3.3.1-4build1"
}
]
},
"package": {
"ecosystem": "Ubuntu:26.04:LTS",
"name": "jline3",
"purl": "pkg:deb/ubuntu/jline3@3.3.1-4build1?arch=source\u0026distro=resolute"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"3.3.1-4",
"3.3.1-4build1"
]
}
],
"aliases": [],
"details": "JLine is a Java library for handling console input. Prior to 3.30.14, 4.0.16, and 4.2.1, the JLine3 Telnet server remote-telnet module does not apply an upper bound to terminal dimensions received via the Telnet NAWS option, and TelnetIO.handleNAWS() in TelnetIO.java:856-879 reads client-supplied width and height as 16-bit unsigned integers and passes values such as 65535x65535 to setTerminalGeometry(), allowing an unauthenticated remote attacker to repeatedly alternate values and trigger continuous expensive rendering work that causes CPU exhaustion and denial of service. This issue is fixed in versions 3.30.14, 4.0.16, and 4.2.1.",
"id": "UBUNTU-CVE-2026-56741",
"modified": "2026-07-29T07:59:16Z",
"published": "2026-07-17T22:17:00Z",
"references": [
{
"type": "REPORT",
"url": "https://ubuntu.com/security/CVE-2026-56741"
},
{
"type": "REPORT",
"url": "https://www.cve.org/CVERecord?id=CVE-2026-56741"
},
{
"type": "REPORT",
"url": "https://github.com/jline/jline3/security/advisories/GHSA-2r2c-cx56-8933"
},
{
"type": "REPORT",
"url": "https://github.com/jline/jline3/pull/2000"
}
],
"related": [],
"schema_version": "1.7.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
"type": "CVSS_V3"
},
{
"score": "medium",
"type": "Ubuntu"
}
],
"upstream": [
"CVE-2026-56741"
]
}
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Sightings
| Author | Source | Type | Date | Other |
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Nomenclature
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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
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Related by attack behaviour
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