Executive Summary

CVE-2026-4736 is an Improper Handling of Values vulnerability found in the No-Chicken Echo-Mate software, specifically in the netfilter modules such as nf_tables.H, nft_byteorder.C, and nft_meta.C. The issue arises from the function nft_byteorder_eval() in the file nft_byteorder.c, where pointer arithmetic was incorrectly handled. This vulnerability is due to the code being cloned from the Linux kernel without incorporating a critical upstream security patch.

The vulnerability was fixed by applying the same security patch that was applied upstream in the Linux kernel (commit c301f09), which corrects the pointer arithmetic issues in nft_byteorder_eval().

Useful 0 Not Useful 0

Impact Analysis

This vulnerability can lead to security risks due to improper handling of values in the affected function. Since it involves pointer arithmetic errors, it could potentially be exploited to cause incorrect program behavior, memory corruption, or other unintended effects that compromise the security or stability of the system running Echo-Mate before version V250329.

Given the CVSS base score of 7.3, the vulnerability is considered high severity, indicating a significant impact on confidentiality, integrity, and availability if exploited.

Useful 0 Not Useful 0

Compliance Impact

I don't know

Useful 0 Not Useful 0

Detection Guidance

Detection of this vulnerability involves verifying if the affected Echo-Mate software version is before V250329 and if the vulnerable function nft_byteorder_eval() in the file nft_byteorder.c is unpatched.

You can check the version of Echo-Mate installed on your system to see if it is older than V250329.

Additionally, inspecting the source code or binaries for the presence of the vulnerable code (pointer arithmetic issues in nft_byteorder_eval) can help confirm vulnerability.

Since this vulnerability relates to kernel netfilter modules, you might also monitor for unusual network behavior or crashes related to netfilter functionality.

Specific commands to check the version or presence of the vulnerable code might include:

• Check Echo-Mate version: `echo-mate --version` or check package manager info.
• Search for vulnerable files: `grep -r nft_byteorder_eval /path/to/echo-mate/source`
• Check kernel modules loaded: `lsmod | grep netfilter`
• Monitor system logs for netfilter related errors: `dmesg | grep nft_byteorder` or `journalctl -k | grep netfilter`

Useful 0 Not Useful 0

Mitigation Strategies

The immediate mitigation step is to upgrade Echo-Mate to version V250329 or later, which includes the security patch fixing the vulnerability in nft_byteorder_eval().

If upgrading is not immediately possible, applying the security patch from the upstream Linux kernel (commit c301f09) to the nft_byteorder.c file in your Echo-Mate source code can mitigate the issue.

Additionally, restrict local access to the affected system since the vulnerability requires local access with low privileges.

Monitor system and network behavior closely for any signs of exploitation.

Useful 0 Not Useful 0