In the Linux kernel, a vulnerability has been resolved relating to the skb_partial_csum_set() function, which addresses the handling of the transport header magic value. The vulnerability allows erroneous setting of the transport header to a special value (0xFFFF), potentially leading to issues with data handling. Although currently only fuzzers can exploit this, it highlights a critical area of concern.
This vulnerability has a CVSS score of 5.5, classifying it as medium severity. Its impact is particularly notable, as it can lead to high availability issues while confidentiality and integrity remain unaffected. Given its nature, organizations should prioritize addressing this vulnerability within their security patch cycles.
Risk to organizations includes service disruptions, especially in environments relying heavily on Linux kernel functionalities. With the potential for local attackers to manipulate the transport header, the urgency for patching is elevated; thus, organizations should schedule remediation as soon as possible.
Currently, there are no known exploits or public proof-of-concept code related to this vulnerability, but organizations should remain vigilant and monitor their systems for any signs of exploitation attempts.
Vulnerability Details
The vulnerability was published on September 18, 2025. It specifically affects the Linux kernel versions starting from 5.19 up to, but not including, 6.1.30, and also includes versions from 6.2 to below 6.3.4, as well as the 6.4 release candidate 1. The CWE classification associated with this vulnerability is CWE-401.
Technical Analysis
The root cause of this vulnerability lies in the improper handling of the skb->transport_header value, which can erroneously be set to 0xFFFF. This misconfiguration can occur when the kernel receives malformed packets, leading to unintended behavior in network communications.
The attack vector is local, meaning that an attacker must have access to the local system to exploit this vulnerability. The complexity of the attack is low, as the conditions for triggering the vulnerability can be easily reproduced in a controlled environment. No user interaction is required, making it easier for attackers to exploit this issue if they have local access.
In terms of impact, the vulnerability has a high availability impact, meaning that it can lead to service disruptions. However, it does not affect confidentiality or integrity, which makes the risk profile somewhat limited to operational downtime.
Risk & Impact Analysis
Organizations running the affected Linux kernel versions may face significant risks if this vulnerability is exploited. Given the local attack vector, the potential blast radius could include any systems where local network access is available. The urgency for patching this vulnerability is assessed as high due to the local nature of the exploit and the availability impact.
Organizations should address this vulnerability in their priority patch cycle. Failure to do so could result in operational disruptions and a compromised network environment.
Exploitation Status
Signal | Status |
|---|---|
Known Exploit | No |
Public PoC | No |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
The following versions of the Linux kernel are affected by this vulnerability: - All versions starting from 5.19 to below 6.1.30 - Versions from 6.2 to below 6.3.4 - 6.4 release candidate 1.
Mitigation & Remediation
Organizations should apply the necessary patches as outlined in the following references to mitigate this vulnerability:
Linux Kernel Patch Reference 1, Linux Kernel Patch Reference 2, Linux Kernel Patch Reference 3
In the absence of an immediate patch, organizations may consider implementing network controls to restrict access to local systems and monitoring for unusual activity that might indicate exploitation attempts.
Detection Guidance
To ensure that systems are not being exploited, organizations should monitor for the following indicators:
Log entries that indicate unexpected alterations to skb->transport_header, unusual packet constructions, or abnormal CPU spikes that coincide with network activity.
AppSecure Threat Intelligence Insight
This vulnerability highlights the importance of robust input validation mechanisms in network protocols. Security teams should take this opportunity to review their existing kernel configurations, focusing on the robustness of their transport layer implementations.
Moreover, organizations should enhance their security posture by investing in continuous security testing and adopting a proactive stance toward vulnerability management. To learn more about effective strategies, see our resources on penetration testing methodologies and vulnerability management best practices.
Lastly, organizations must keep abreast of emerging vulnerabilities and adapt their defenses accordingly to mitigate risks effectively.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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