UBUNTU-CVE-2026-56740 (CVE-2026-56740)
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 limit the number of environment variables a client may inject via the Telnet NEW-ENVIRON option, and TelnetIO.readNEVariables() in TelnetIO.java:1127-1180 stores each variable pair in a HashMap held by ConnectionData, allowing an unauthenticated attacker to flood unique variable pairs before the terminating IAC SE byte and exhaust JVM heap memory with an OutOfMemoryError. 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"
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],
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]
},
{
"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": [
{
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],
"type": "ECOSYSTEM"
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],
"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 limit the number of environment variables a client may inject via the Telnet NEW-ENVIRON option, and TelnetIO.readNEVariables() in TelnetIO.java:1127-1180 stores each variable pair in a HashMap held by ConnectionData, allowing an unauthenticated attacker to flood unique variable pairs before the terminating IAC SE byte and exhaust JVM heap memory with an OutOfMemoryError. This issue is fixed in versions 3.30.14, 4.0.16, and 4.2.1.",
"id": "UBUNTU-CVE-2026-56740",
"modified": "2026-07-29T07:59:16Z",
"published": "2026-07-17T22:17:00Z",
"references": [
{
"type": "REPORT",
"url": "https://ubuntu.com/security/CVE-2026-56740"
},
{
"type": "REPORT",
"url": "https://www.cve.org/CVERecord?id=CVE-2026-56740"
},
{
"type": "REPORT",
"url": "https://github.com/jline/jline3/security/advisories/GHSA-47qp-hqvx-6r3f"
},
{
"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-2026-56740"
]
}
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
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- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
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- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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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.
Browse all ATT&CK techniques and the vulnerabilities related to each.
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
Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.
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