Overview
The cybersecurity landscape is ever-changing, and new vulnerabilities are discovered regularly. One such vulnerability is CVE-2025-49809, affecting the mtr utility up to version 0.95. Mtr is a network diagnostic tool often used in the Unix-like operating systems. This vulnerability is particularly concerning because it can lead to system compromise or data leakage, posing a serious threat to the integrity, confidentiality, and availability of data and systems.
This vulnerability can affect anyone using a Unix-like operating system, including macOS where mtr may often have Sudo rules, due to Homebrew not installing setuid binaries. It’s crucial that all users and administrators of these systems be aware of this vulnerability, understand its implications, and take immediate steps to mitigate its potential impact.
Vulnerability Summary
CVE ID: CVE-2025-49809
Severity: High (7.8 CVSS v3 score)
Attack Vector: Network
Privileges Required: Low
User Interaction: None
Impact: Potential system compromise or data leakage
Affected Products
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Product | Affected Versions
mtr | up to and including 0.95
How the Exploit Works
This vulnerability stems from mtr’s mishandling of the execution of a program specified by the MTR_PACKET environment variable in certain privileged contexts. Exploitation occurs when an attacker is able to manipulate this environment variable to execute arbitrary code with elevated privileges on the target system, leading to potential system compromise or data leakage.
Conceptual Example Code
Below is a conceptual example of how this vulnerability might be exploited:
# Setting the MTR_PACKET environment variable to a malicious program
export MTR_PACKET=/path/to/malicious_program
# Running mtr with elevated privileges
sudo mtr target.example.comIn this example, the malicious_program would be executed with elevated privileges when mtr is run, potentially leading to system compromise or data leakage.
Mitigation Guidance
Users and administrators affected by this vulnerability are urged to apply the vendor-provided patch as soon as possible. In the event that the patch cannot be applied immediately, the use of a Web Application Firewall (WAF) or Intrusion Detection System (IDS) can serve as temporary mitigation. However, these methods should not be treated as a long-term solution, as they may not fully protect against all potential exploits of this vulnerability.