UBUNTU-CVE-2026-44838 (CVE-2026-44838)
Vulnerability from osv_ubuntu – Published: 2026-05-27 15:16 – Updated: 2026-06-03 11:25 – Source website
Withdrawn 2026-06-04
VLAI
Details
RabbitMQ is a messaging and streaming broker. From 4.2.0 to before 4.2.4, RabbitMQ's MQTT plugin allows for topic-level authorization using regular expressions with variable substitution. Administrators can create patterns such as ^{client_id}-sensors$ to restrict user access to topics that include their client ID. However, the client_id is provided by the user in the MQTT CONNECT packet and is inserted into the regex pattern without escaping special regex characters. This flaw enables an authenticated MQTT user to inject regex operators to bypass authorization. This vulnerability is fixed in 4.2.4 and 4.3.0.
Severity
N/A (UNKNOWN)
References
{
"affected": [
{
"ecosystem_specific": {
"binaries": [
{
"binary_name": "rabbitmq-server",
"binary_version": "3.5.7-1ubuntu0.16.04.4+esm2"
}
]
},
"package": {
"ecosystem": "Ubuntu:Pro:16.04:LTS",
"name": "rabbitmq-server",
"purl": "pkg:deb/ubuntu/rabbitmq-server@3.5.7-1ubuntu0.16.04.4+esm2?arch=source\u0026distro=esm-infra/xenial"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"3.5.4-1",
"3.5.4-3",
"3.5.4-3.1",
"3.5.7-1",
"3.5.7-1ubuntu0.16.04.1",
"3.5.7-1ubuntu0.16.04.2",
"3.5.7-1ubuntu0.16.04.4",
"3.5.7-1ubuntu0.16.04.4+esm1",
"3.5.7-1ubuntu0.16.04.4+esm2"
]
},
{
"ecosystem_specific": {
"binaries": [
{
"binary_name": "rabbitmq-server",
"binary_version": "3.6.10-1ubuntu0.5"
}
]
},
"package": {
"ecosystem": "Ubuntu:18.04:LTS",
"name": "rabbitmq-server",
"purl": "pkg:deb/ubuntu/rabbitmq-server@3.6.10-1ubuntu0.5?arch=source\u0026distro=bionic"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"3.6.10-1",
"3.6.10-1ubuntu0.1",
"3.6.10-1ubuntu0.3",
"3.6.10-1ubuntu0.4",
"3.6.10-1ubuntu0.5"
]
},
{
"ecosystem_specific": {
"binaries": [
{
"binary_name": "rabbitmq-server",
"binary_version": "3.8.3-0ubuntu0.3"
}
]
},
"package": {
"ecosystem": "Ubuntu:20.04:LTS",
"name": "rabbitmq-server",
"purl": "pkg:deb/ubuntu/rabbitmq-server@3.8.3-0ubuntu0.3?arch=source\u0026distro=focal"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"3.7.8-4ubuntu2",
"3.7.18-1",
"3.8.2-0ubuntu1",
"3.8.2-0ubuntu1.1",
"3.8.2-0ubuntu1.2",
"3.8.2-0ubuntu1.3",
"3.8.2-0ubuntu1.4",
"3.8.2-0ubuntu1.5",
"3.8.3-0ubuntu0.1",
"3.8.3-0ubuntu0.2",
"3.8.3-0ubuntu0.3"
]
},
{
"ecosystem_specific": {
"binaries": [
{
"binary_name": "rabbitmq-server",
"binary_version": "3.9.27-0ubuntu0.2"
}
]
},
"package": {
"ecosystem": "Ubuntu:22.04:LTS",
"name": "rabbitmq-server",
"purl": "pkg:deb/ubuntu/rabbitmq-server@3.9.27-0ubuntu0.2?arch=source\u0026distro=jammy"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"3.8.9-3ubuntu1",
"3.9.8-1",
"3.9.8-2",
"3.9.8-3",
"3.9.8-5",
"3.9.8-6",
"3.9.13-1",
"3.9.13-1ubuntu0.22.04.1",
"3.9.13-1ubuntu0.22.04.2",
"3.9.27-0ubuntu0.1",
"3.9.27-0ubuntu0.2"
]
},
{
"ecosystem_specific": {
"binaries": [
{
"binary_name": "rabbitmq-server",
"binary_version": "3.12.1-1ubuntu1.4"
}
]
},
"package": {
"ecosystem": "Ubuntu:24.04:LTS",
"name": "rabbitmq-server",
"purl": "pkg:deb/ubuntu/rabbitmq-server@3.12.1-1ubuntu1.4?arch=source\u0026distro=noble"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"3.12.1-1",
"3.12.1-1ubuntu1",
"3.12.1-1ubuntu1.2",
"3.12.1-1ubuntu1.4"
]
},
{
"ecosystem_specific": {
"binaries": [
{
"binary_name": "rabbitmq-server",
"binary_version": "4.0.5-8ubuntu2.1"
}
]
},
"package": {
"ecosystem": "Ubuntu:25.10",
"name": "rabbitmq-server",
"purl": "pkg:deb/ubuntu/rabbitmq-server@4.0.5-8ubuntu2.1?arch=source\u0026distro=questing"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"4.0.5-2ubuntu2",
"4.0.5-6ubuntu1",
"4.0.5-8ubuntu1",
"4.0.5-8ubuntu2",
"4.0.5-8ubuntu2.1"
]
},
{
"ecosystem_specific": {
"binaries": [
{
"binary_name": "rabbitmq-server",
"binary_version": "4.0.5-10ubuntu5"
}
]
},
"package": {
"ecosystem": "Ubuntu:26.04:LTS",
"name": "rabbitmq-server",
"purl": "pkg:deb/ubuntu/rabbitmq-server@4.0.5-10ubuntu5?arch=source\u0026distro=resolute"
},
"ranges": [
{
"events": [
{
"introduced": "0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"4.0.5-8ubuntu2",
"4.0.5-10ubuntu1",
"4.0.5-10ubuntu2",
"4.0.5-10ubuntu3",
"4.0.5-10ubuntu4",
"4.0.5-10ubuntu5"
]
}
],
"aliases": [],
"details": "RabbitMQ is a messaging and streaming broker. From 4.2.0 to before 4.2.4, RabbitMQ\u0027s MQTT plugin allows for topic-level authorization using regular expressions with variable substitution. Administrators can create patterns such as ^{client_id}-sensors$ to restrict user access to topics that include their client ID. However, the client_id is provided by the user in the MQTT CONNECT packet and is inserted into the regex pattern without escaping special regex characters. This flaw enables an authenticated MQTT user to inject regex operators to bypass authorization. This vulnerability is fixed in 4.2.4 and 4.3.0.",
"id": "UBUNTU-CVE-2026-44838",
"modified": "2026-06-03T11:25:22Z",
"published": "2026-05-27T15:16:00Z",
"references": [
{
"type": "REPORT",
"url": "https://ubuntu.com/security/CVE-2026-44838"
},
{
"type": "REPORT",
"url": "https://www.cve.org/CVERecord?id=CVE-2026-44838"
},
{
"type": "REPORT",
"url": "https://github.com/rabbitmq/rabbitmq-server/security/advisories/GHSA-x866-xp2g-cx8v"
}
],
"related": [],
"schema_version": "1.7.0",
"severity": [
{
"score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:L/VI:L/VA:L/SC:H/SI:H/SA:N",
"type": "CVSS_V4"
},
{
"score": "medium",
"type": "Ubuntu"
}
],
"upstream": [
"CVE-2026-44838"
],
"withdrawn": "2026-06-04T20:32:00Z"
}
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Sightings
| Author | Source | Type | Date | Other |
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Nomenclature
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vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
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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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