Overview
CVE-2025-59518 is a critical vulnerability discovered in LemonLDAP::NG, a popular web Single Sign-On (SSO) software. The vulnerability allows for Operating System (OS) command injection, a high-risk exploit that could potentially lead to system compromise or data leakage. The concerning aspect of this vulnerability lies in the fact that it affects versions of LemonLDAP::NG prior to 2.16.7 and 2.17 through 2.21 before 2.21.3. This vulnerability is particularly significant as LemonLDAP::NG is widely used in enterprise networks for managing user authentication and authorization.
Vulnerability Summary
CVE ID: CVE-2025-59518
Severity: High (CVSS: 8.0)
Attack Vector: Network
Privileges Required: Low (Administrator access)
User Interaction: Required
Impact: Potential system compromise or data leakage
Affected Products
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Product | Affected Versions
LemonLDAP::NG | Before 2.16.7, 2.17 – 2.21 before 2.21.3
How the Exploit Works
The vulnerability arises from an OS command injection flaw present in the Safe jail of LemonLDAP::NG. An administrator with the ability to edit a rule evaluated by the Safe jail can execute arbitrary commands on the server. This is due to the application’s failure to localize the underscore (_) during rule evaluation. This oversight enables malicious actors to inject and execute harmful commands, potentially leading to system compromise or data leakage.
Conceptual Example Code
Consider the following hypothetical scenario where the adversary uses a shell command injection to exploit the vulnerability:
$ curl -X POST "http://target.example.com/lemonldap/rule" \
-H "Content-Type: application/x-www-form-urlencoded" \
-d "rule=; rm -rf / --no-preserve-root ;"In this conceptual example, the malicious actor sends a POST request to the rule evaluation endpoint of the LemonLDAP::NG application. The rule parameter contains a malicious payload (`; rm -rf / –no-preserve-root ;`) that, when evaluated, executes the OS command to delete all files in the system.
Please note that the above example is a conceptual demonstration of how the exploit might work. The actual exploitation would depend on numerous factors, including the specific version of LemonLDAP::NG installed, the environment it’s running in, and the level of access the attacker has.
Mitigation Measures
Users of affected versions of LemonLDAP::NG are advised to apply the vendor patch immediately. Those who cannot apply the update promptly can use Web Application Firewalls (WAF) or Intrusion Detection Systems (IDS) as temporary mitigation measures. However, these are only stop-gap solutions and do not address the root cause of the vulnerability. Therefore, updating to a patched version of the software is the recommended course of action.
