CVE-2026-55426
linuxfabrik-lib provides Python modules for database access, caching, shell execution, and API integrations, and Linuxfabrik Monitoring Plugins uses those modules to run external monitoring commands. From the earliest affected releases until linuxfabrik-lib 5.0.0 and Linuxfabrik Monitoring Plugins 6.0.0, check plugins embedded user-controlled values in command strings passed to lib.shell.shell_exec(), which split strings at pipe characters and executed the resulting commands.
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In check-plugins/restic-check/restic-check, the --repo parameter could inject a pipe-delimited command into a constructed restic invocation, and sudo-authorized execution allowed a compromised nagios or icinga account to run that command as root. The shared library also accepted command strings and a shell parameter, while numerous plugins constructed external commands from attacker-influenced arguments. The fixes require argv lists, always use shell=False, remove pipe splitting, and reject option-like positional values through lib.shell.safe_cli_value(). These issues are fixed in linuxfabrik-lib 5.0.0 and Linuxfabrik Monitoring Plugins 6.0.0.
CVSS
- Versión: 3.1
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Puntuación base: 7.8
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 0.21%
- Percentil entre todas las CVEs puntuadas: 10
- Fecha de la puntuación: 6/10/2026
EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).
🎯 Técnicas ATT&CK
Cómo se explota esta vulnerabilidad y qué consigue el atacante, en el lenguaje de MITRE ATT&CK.
- Explotación
T1068Exploitation for Privilege Escalationprivilege escalation85 % - Impacto principal
T1059Command and Scripting Interpreterexecution90 % - Impacto secundario
T1548.004Elevated Execution with Promptprivilege escalation80 %
AV:L + PR:L permite escalada local vía inyección de comandos en parámetros. El atacante con cuenta nagios/icinga ejecuta comandos como root mediante pipe splitting en lib.shell.shell_exec().
Inferido por nuestro agente de análisis a partir de la descripción oficial, el vector CVSS y la CWE, y comprobado por un supervisor. Puede contener errores.
🛡️ Mitigaciones ATT&CK que cubren estas técnicas
Tecnologías afectadas (2)
⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.
CWE
- CWE-78
Referencias
- https://github.com/Linuxfabrik/lib/blob/main/CHANGELOG.md
- https://github.com/Linuxfabrik/lib/releases/tag/v5.0.0
- https://github.com/Linuxfabrik/monitoring-plugins/blob/main/CHANGELOG.md
- https://github.com/Linuxfabrik/monitoring-plugins/commit/23bb570f41fc8d9caf30b30074bba0e3db1b357a
- https://github.com/Linuxfabrik/monitoring-plugins/releases/tag/v6.0.0
- https://github.com/Linuxfabrik/monitoring-plugins/security/advisories/GHSA-798h-hpph-m24j
JSON original (NVD)
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{
"id": "CVE-2026-55426",
"cveTags": [],
"metrics": {
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"id": "CVE-2026-55426",
"role": "CISA Coordinator",
"options": [
{
"exploitation": "poc"
},
{
"automatable": "no"
},
{
"technicalImpact": "total"
}
],
"version": "2.0.3",
"timestamp": "2026-08-19T20:31:18.922121Z"
}
}
],
"cvssMetricV31": [
{
"type": "Secondary",
"source": "security-advisories@github.com",
"cvssData": {
"scope": "UNCHANGED",
"version": "3.1",
"baseScore": 7.8,
"attackVector": "LOCAL",
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"integrityImpact": "HIGH",
"userInteraction": "NONE",
"attackComplexity": "LOW",
"availabilityImpact": "HIGH",
"privilegesRequired": "LOW",
"confidentialityImpact": "HIGH"
},
"impactScore": 5.9,
"exploitabilityScore": 1.8
}
]
},
"affected": [
{
"source": "security-advisories@github.com",
"affectedData": [
{
"vendor": "Linuxfabrik",
"product": "monitoring-plugins",
"versions": [
{
"status": "affected",
"version": "< 6.0.0"
}
]
},
{
"vendor": "Linuxfabrik",
"product": "lib",
"versions": [
{
"status": "affected",
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}
]
}
]
}
],
"published": "2026-08-18T21:16:36.460",
"references": [
{
"url": "https://github.com/Linuxfabrik/lib/blob/main/CHANGELOG.md",
"source": "security-advisories@github.com"
},
{
"url": "https://github.com/Linuxfabrik/lib/releases/tag/v5.0.0",
"source": "security-advisories@github.com"
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{
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{
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"source": "security-advisories@github.com"
},
{
"url": "https://github.com/Linuxfabrik/monitoring-plugins/releases/tag/v6.0.0",
"source": "security-advisories@github.com"
},
{
"url": "https://github.com/Linuxfabrik/monitoring-plugins/security/advisories/GHSA-798h-hpph-m24j",
"source": "security-advisories@github.com"
}
],
"vulnStatus": "Deferred",
"weaknesses": [
{
"type": "Secondary",
"source": "security-advisories@github.com",
"description": [
{
"lang": "en",
"value": "CWE-78"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "linuxfabrik-lib provides Python modules for database access, caching, shell execution, and API integrations, and Linuxfabrik Monitoring Plugins uses those modules to run external monitoring commands. From the earliest affected releases until linuxfabrik-lib 5.0.0 and Linuxfabrik Monitoring Plugins 6.0.0, check plugins embedded user-controlled values in command strings passed to lib.shell.shell_exec(), which split strings at pipe characters and executed the resulting commands. In check-plugins/restic-check/restic-check, the --repo parameter could inject a pipe-delimited command into a constructed restic invocation, and sudo-authorized execution allowed a compromised nagios or icinga account to run that command as root. The shared library also accepted command strings and a shell parameter, while numerous plugins constructed external commands from attacker-influenced arguments. The fixes require argv lists, always use shell=False, remove pipe splitting, and reject option-like positional values through lib.shell.safe_cli_value(). These issues are fixed in linuxfabrik-lib 5.0.0 and Linuxfabrik Monitoring Plugins 6.0.0."
}
],
"lastModified": "2026-09-09T21:13:25.910",
"sourceIdentifier": "security-advisories@github.com"
}