CVE-2026-55426 (GCVE-0-2026-55426)

Vulnerability from cvelistv5 – Published: 2026-08-18 20:57 – Updated: 2026-08-18 20:57
VLAI
Title
linuxfabrik-lib: Local privilege escalation using embedded command
Summary
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.
Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CWE
  • CWE-78 - Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
Assigner
References
Impacted products
Vendor Product Version CPE status
Linuxfabrik monitoring-plugins Affected: < 6.0.0
guessed Create a notification for this product.
Linuxfabrik lib Affected: < 5.0.0
guessed Create a notification for this product.
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "product": "monitoring-plugins",
          "vendor": "Linuxfabrik",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 6.0.0"
            }
          ]
        },
        {
          "product": "lib",
          "vendor": "Linuxfabrik",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 5.0.0"
            }
          ]
        }
      ],
      "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."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "LOCAL",
            "availabilityImpact": "HIGH",
            "baseScore": 7.8,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "HIGH",
            "integrityImpact": "HIGH",
            "privilegesRequired": "LOW",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-78",
              "description": "CWE-78: Improper Neutralization of Special Elements used in an OS Command (\u0027OS Command Injection\u0027)",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-18T20:57:59.873Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
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          "name": "https://github.com/Linuxfabrik/monitoring-plugins/security/advisories/GHSA-798h-hpph-m24j",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/Linuxfabrik/monitoring-plugins/security/advisories/GHSA-798h-hpph-m24j"
        },
        {
          "name": "https://github.com/Linuxfabrik/monitoring-plugins/commit/23bb570f41fc8d9caf30b30074bba0e3db1b357a",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/Linuxfabrik/monitoring-plugins/commit/23bb570f41fc8d9caf30b30074bba0e3db1b357a"
        },
        {
          "name": "https://github.com/Linuxfabrik/lib/blob/main/CHANGELOG.md",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/Linuxfabrik/lib/blob/main/CHANGELOG.md"
        },
        {
          "name": "https://github.com/Linuxfabrik/lib/releases/tag/v5.0.0",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/Linuxfabrik/lib/releases/tag/v5.0.0"
        },
        {
          "name": "https://github.com/Linuxfabrik/monitoring-plugins/blob/main/CHANGELOG.md",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/Linuxfabrik/monitoring-plugins/blob/main/CHANGELOG.md"
        },
        {
          "name": "https://github.com/Linuxfabrik/monitoring-plugins/releases/tag/v6.0.0",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/Linuxfabrik/monitoring-plugins/releases/tag/v6.0.0"
        }
      ],
      "source": {
        "advisory": "GHSA-798h-hpph-m24j",
        "discovery": "UNKNOWN"
      },
      "title": "linuxfabrik-lib: Local privilege escalation using embedded command"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-55426",
    "datePublished": "2026-08-18T20:57:59.873Z",
    "dateReserved": "2026-06-16T21:48:43.126Z",
    "dateUpdated": "2026-08-18T20:57:59.873Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-55426",
      "date": "2026-08-20",
      "epss": "0.00197",
      "percentile": "0.09886"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-55426\",\"sourceIdentifier\":\"security-advisories@github.com\",\"published\":\"2026-08-18T21:16:36.460\",\"lastModified\":\"2026-08-18T21:16:36.460\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"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.\"}],\"affected\":[{\"source\":\"security-advisories@github.com\",\"affectedData\":[{\"vendor\":\"Linuxfabrik\",\"product\":\"monitoring-plugins\",\"versions\":[{\"version\":\"\u003c 6.0.0\",\"status\":\"affected\"}]},{\"vendor\":\"Linuxfabrik\",\"product\":\"lib\",\"versions\":[{\"version\":\"\u003c 5.0.0\",\"status\":\"affected\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"security-advisories@github.com\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H\",\"baseScore\":7.8,\"baseSeverity\":\"HIGH\",\"attackVector\":\"LOCAL\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"LOW\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":1.8,\"impactScore\":5.9}]},\"weaknesses\":[{\"source\":\"security-advisories@github.com\",\"type\":\"Primary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-78\"}]}],\"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\"},{\"url\":\"https://github.com/Linuxfabrik/monitoring-plugins/blob/main/CHANGELOG.md\",\"source\":\"security-advisories@github.com\"},{\"url\":\"https://github.com/Linuxfabrik/monitoring-plugins/commit/23bb570f41fc8d9caf30b30074bba0e3db1b357a\",\"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\"}]}}"
  }
}



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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.

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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
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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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