← Vulnerability feed

Vulnerability record · CVE-2026-55426 · published 18 August 2026

CVE-2026-55426: OS command injection vulnerability

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.

7.8 CVSS 3.1 High EPSS 0.21% · top 89.8% CWE-78 · OS command injection Deferred
7.8CVSS 3.1 base score
0.21%EPSS exploitation probability, 30 days
NoNot in CISA KEV
0Affected product versions listed by NVD
6References
9 Sep 2026Last modified by NVD

Description

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.

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

References

LinkTags
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

Track CVE-2026-55426 inside VULONE

Watch it alongside the ransomware crews, C2 infrastructure and forum chatter that reference it, query it through the API and pull it into your SIEM over TAXII.

Start free Open in platform

Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

8.8CVE-2026-53266Linux kernel ebtables SNAT out-of-bounds write in ARP rewriteThe ebtables SNAT target rewrites the ARP sender hardware address via skb_store_bits() without first making that range writable. When the ARP SHA byt…KEVEPSS 0.65%analysed8.8CVE-2026-87491Google Chrome V8 out-of-bounds write enables sandbox code executionChrome before 153.0.8010.36 contains an out-of-bounds write in the V8 JavaScript engine. A crafted HTML page can trigger the memory corruption, and b…KEVEPSS 3.1%analysed9.8CVE-2025-25249Fortinet FortiOS and FortiSwitchManager heap buffer overflow via crafted packetsA heap-based buffer overflow (CWE-122/CWE-787) in Fortinet FortiOS 6.4 through 7.6.3 and FortiSwitchManager 7.0 through 7.2.6 lets an unauthenticated…KEVEPSS 3.9%analysed7.8CVE-2026-83549SonicWall SMA1000 AMC OS Command InjectionThe SMA1000 Appliance Management Console contains an OS command injection flaw (CWE-78) that lets an authenticated administrator execute arbitrary op…KEVEPSS 11%analysed10.0CVE-2026-49869Kestra OSS auth bypass via path suffix match enables RCEKestra OSS AuthenticationFilter whitelists the public config endpoint using request.getPath().endsWith("/configs"), a suffix match instead of an exac…KEVEPSS 2.1%analysed7.8CVE-2026-53362Linux kernel IPv6 UDP paged allocation out-of-bounds write__ip6_append_data() in the Linux kernel mis-accounts fraggap on the paged-allocation path, leaving the linear skb area undersized while pagedlen is o…KEVEPSS 0.71%analysed7.8CVE-2022-0995Linux kernel watch_queue out-of-bounds writeThe Linux kernel's watch_queue event notification subsystem contains an out-of-bounds write (CWE-787) that can overwrite kernel state. A local user c…KEVEPSS 8.8%analysed8.9CVE-2026-73570Zimbra Collaboration SNMP notification OS command injectionZimbra Collaboration Suite before 10.1.20 contains an OS command injection flaw in SNMP notification processing when the optional zimbra-snmp package…KEVEPSS 12%analysed

Source: NIST National Vulnerability Database (record CVE-2026-55426), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.