CVE-2026-55182
HIGHDescription
LibreNMS is a network monitoring system. In versions from 21.6.0 up to 26.5.0, the Signal alert transport is vulnerable to command injection because the signal-cli path and the Recipient field of an alert transport entry are insufficiently escaped before being passed to an exec call. An authenticated administrator can craft a transport entry whose Recipient contains shell metacharacters and whose path points to the bundled composer_wrapper.php script, which itself passes attacker-controlled input to further unsafe exec calls. By chaining these calls, the administrator can execute arbitrary operating-system commands on the LibreNMS host. This issue is fixed in version 26.5.0.
How to fix
No published remediation has been found for this vulnerability's affected products yet.
Mitigation guidance may be in the linked vendor advisories in the References section below.
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CVSS v4 Vector
Exploitability
Impact
CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Exploit Intelligence
Moderate risk: more likely to be exploited than 64% of all known CVEs.
References
Related Vulnerabilities
Other CWE-77 (Command Injection) vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2024-3400 | Critical | 10.0 | 100% | KEV + Ransom | - |
| CVE-2024-21887 | Critical | 9.1 | 100% | KEV + Ransom | - |
| CVE-2023-1671 | Critical | 9.8 | 100% | KEV | Fix |
| CVE-2023-1389 | High | 8.8 | 100% | KEV | Fix |
| CVE-2021-1498 | Critical | 9.8 | 100% | KEV | Fix |
| CVE-2012-1823 | Critical | 9.8 | 100% | KEV | Fix |
Common questions
How do I fix CVE-2026-55182?
No published fix for CVE-2026-55182 has been found yet. Check the linked vendor advisories for guidance as it becomes available.
Is CVE-2026-55182 being actively exploited?
Not that we know of. CVE-2026-55182 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 1.1% is the estimated probability that it will be exploited in the next 30 days. That is higher than 64% of all scored CVEs.
How severe is CVE-2026-55182?
CVE-2026-55182 has a CVSS v4 base score of 8.6, rated high. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
Embed a live status badge for CVE-2026-55182
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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-08-27.