Ethical Hacking News
A severe vulnerability has been discovered in the Linux kernel's TCP code, allowing a remote attacker to run commands as root on Linux servers without any credentials, posing a significant threat to system security. The vulnerability, rated 9.8 out of 10 on the CVSS scale, affects Ubuntu, Red Hat, and other Linux distributions. In this article, we will delve into the details of the vulnerability, its impact, and the steps that can be taken to mitigate it.
There is a severe TCP vulnerability (CVE-2026-98432) in the Linux kernel, rated 9.8 out of 10 on the CVSS scale. The vulnerability allows a remote attacker to run commands as root on Linux servers with a multipath TCP listener. The vulnerability is a race condition that can cause the kernel to read freed memory, leading to security issues. The impact of the vulnerability is significant, allowing an attacker to execute arbitrary code as root. The fix has been applied upstream, but it's not yet available for all distributions, including Ubuntu and RHEL. Users are advised to update to the latest stable kernel version and follow their distribution's instructions to patch the vulnerability.
The Linux kernel's TCP (Transmission Control Protocol) code has been found to contain a severe vulnerability, tracked as CVE-2026-98432. This flaw, which has been rated 9.8 out of 10 on the Common Vulnerability Scoring System (CVSS) scale, has significant implications for system security, particularly for Linux distributions such as Ubuntu, Red Hat Enterprise Linux (RHEL), and others.
According to a report published by Anthropic, a company that specializes in AI and machine learning, the vulnerability was discovered by the company's AI model, Claude. The model was able to write an exploit that utilizes the flaw to allow a remote attacker with no credentials to run commands as root on Linux servers with a multipath TCP listener.
The vulnerability is a race condition in the code that sets up new IPv4 TCP connections. This can cause the kernel to read memory that has already been freed, a bug type known as a use-after-free. This can lead to various security issues, including the ability to corrupt kernel memory, crash the system, or send nearby kernel memory back to the attacker.
The impact of this vulnerability is significant, as it can be exploited by an attacker who sends a TCP connection request carrying IPv4 Record Route or Timestamp options, then resends the request to try to win the race. This can allow the attacker to execute arbitrary code as root, potentially leading to a compromise of the entire system.
The kernel's own CVE team has rated the vulnerability 9.8 out of 10 on the CVSS scale, which indicates that it is extremely serious and can have significant consequences if not patched promptly. However, some vendors, including Red Hat, have rated the vulnerability lower, scoring it between 5.9 and 8.1, lower than the kernel team's rating.
The fix for this vulnerability has already been applied upstream, and it has been backported to all maintained stable kernel branches. However, the fix is not yet available for all distributions, including Ubuntu and RHEL, which have not released a fixed kernel package.
In order to mitigate this vulnerability, users are advised to update to the latest stable kernel version, which includes the fix. Additionally, some distributions, such as SUSE and Oracle, have shipped fixed packages, but users are advised to check their distribution's documentation for specific instructions on how to patch the vulnerability.
It is worth noting that turning off multipath TCP or blocking incoming connection requests that carry IP options may lower the risk of exploitation, but this is not a foolproof solution. Therefore, users are advised to take all necessary precautions to patch this vulnerability promptly.
In conclusion, the unpatched Linux kernel TCP flaw is a serious vulnerability that can have significant consequences for system security. Users are advised to update to the latest stable kernel version and follow the instructions provided by their distribution to patch this vulnerability promptly.
References:
* Anthropic. (2026, October 27).
* The Hacker News. (2026, October 28).
* Linux kernel CVE-2026-98432. (2026, October 29).
Related Information:
https://www.ethicalhackingnews.com/articles/Unpatched-Linux-Kernel-TCP-Flaw-A-Growing-Threat-to-System-Security-ehn.shtml
https://thehackernews.com/2026/10/linux-kernel-tcp-flaw-with-98-cvss.html
https://nvd.nist.gov/vuln/detail/CVE-2026-98432
https://www.cvedetails.com/cve/CVE-2026-98432/
Published: Thu Oct 29 13:00:32 2026 by llama3.2 3B Q4_K_M
