How severe is CVE-2026-55182?

No CVSS score has been assigned to CVE-2026-55182 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-55182?

CVE-2026-55182 affects the following packages: librenms/librenms (Packagist). Ecosystems affected: Packagist.

How do I fix CVE-2026-55182?

Update librenms/librenms to 26.5.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-55182 is resolved across your whole dependency graph.

How do I detect CVE-2026-55182 in my Packagist dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for librenms/librenms. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

How do I mitigate CVE-2026-55182 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

How does O3 Security protect against CVE-2026-55182?

O3 pinpoints whether CVE-2026-55182 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is CVE-2026-55182 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-55182 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

When was CVE-2026-55182 published, and has it been updated?

CVE-2026-55182 was published on August 18, 2026 and was last updated on August 18, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐘 Packagist

Not in CISA KEV

CVE-2026-55182

CVE-2026-55182 is a remote code execution vulnerability in librenms/librenms. O3 Security confirms whether CVE-2026-55182 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.

LibreNMS Vulnerable to Remote Code Execution by Signal Alert Transportation module

Published

Aug 18, 2026

Updated

Aug 18, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Aug 18, 2026 · OSV.dev, FIRST.org (EPSS)

Real-World Exposure

1 pkg affected

🐘librenms/librenms

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.

Description

Summary

A vulnerability has been identified that allows an authenticated administrator to execute arbitrary code on the host server. By adding an alert transport entry, an attacker with administrative privileges can execute malicious commands.

Details

The vulnerability is caused by an unsafe exec call in deliverAlert function of LibreNMS/Alert/Transport/Signal.php. Escapes for the path of signal-cli and the Recipient field are insufficient to prevent command-line injection.

The composer_wrapper.php under scripts is also vulnerable to command injection (unsafe exec calls) by passing the injected command as an argument, and it is accepting arguments passed by deliverAlert.

By chaining these unsafe exec calls, malicious admin user can execute any executables in the server's filesystem.

PoC

Under Dashboard -> Alert -> Alert Transports

Create a new Alert Transport entry. a. Select Signal as Transport type. b. Put ../scripts/composer_wrapper.php into Path. c. Put the command to execute under Recipient with ; at the start and the end of string.

. Click Save Transport, and after the popup closed, click Test Transport button under Action of the created Alert Transport entry.

The command is executed. <img width="532" height="216" alt="image" src="https://github.com/user-attachments/assets/d595b0fe-10cc-4050-b4b9-d290b658689d" />

Impact

This vulnerability allows a malicious actor to achieve Remote Code Execution (RCE), potentially leading to complete system compromise, data exfiltration, or lateral movement within the network.

Remediation Advice

Escape user inputs, and avoid passing them directly into exec function. (scripts/composer_wrapper.php) Avoid setting executable paths directly in web interface. Instead, use a config value, and only allow setting executable paths by command line interface. (LibreNMS/Alert/Transport/Signal.php)

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐘Packagist	`librenms/librenms`	≥ 21.6.0&&< 26.5.0	26.5.0

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for librenms/librenms. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update librenms/librenms to 26.5.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-55182 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-55182 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to CVE-2026-55182. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

### Summary A vulnerability has been identified that allows an authenticated administrator to execute arbitrary code on the host server. By adding an alert transport entry, an attacker with administrative privileges can execute malicious commands. ### Details The vulnerability is caused by an unsafe `exec` call in `deliverAlert` function of `LibreNMS/Alert/Transport/Signal.php`. Escapes for the path of `signal-cli` and the `Recipient` field are insufficient to prevent command-line injection. The `composer_wrapper.php` under `scripts` is also vulnerable to command injection (unsafe `exec` ca

O3 Security · Impact-Aware SCA

Is CVE-2026-55182 in your dependencies?

O3 detects CVE-2026-55182 across Packagist dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

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