Idempotent HTB Class Deactivation in Linux Kernel - CVE-2025-37932
Summary
CVE-2025-37932: In the Linux kernel, the following vulnerability has been resolved: sch_htb: make htb_qlen_notify() idempotent htb_qlen_notify() always deactivates the HTB class and in fact could trigger a warning if it is already deact... Affects linux versions 5.10.103-1 – 6.9.9-1. No fix is published. How to fix ↓
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Background
The Linux kernel is a core component of the operating system that manages hardware and software interactions. It provides essential services such as process management, memory management, and device control. The kernel's functionality is critical for system stability and performance. The HTB (Hierarchical Token Bucket) is a queuing discipline used for traffic shaping in networking. This vulnerability affects the HTB class, specifically the htb_qlen_notify() function, which is responsible for notifying changes in queue length.
Vulnerability Detail
CVE-2025-37932 arises from the htb_qlen_notify() function, which is not idempotent. This means that calling this function multiple times can lead to unintended consequences, such as deactivating an already deactivated HTB class and potentially triggering warnings. This behavior can disrupt the operation of callers like fq_codel_dequeue(), leading to performance degradation and instability in network traffic management.
How To Fix
No fixed version is published for this vulnerability.
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Workaround
Currently, there are no specific workarounds mentioned for this vulnerability. However, users can monitor their systems for any unusual behavior related to network traffic management until the patch is applied.
Conclusion
CVE-2025-37932 is a significant vulnerability in the Linux kernel that affects the HTB class's functionality. It is crucial for users to update their systems to the patched version to ensure stability and performance in network traffic management. Monitoring tools like Vulert can assist in identifying vulnerabilities in open-source software.
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FAQ
CVE-2025-37932 is a vulnerability in the Linux kernel related to the HTB class that affects the htb_qlen_notify() function, making it non-idempotent.
The vulnerability can lead to performance issues and instability in network traffic management, affecting the overall system performance.
You can use Vulert to monitor and alert for open-source vulnerabilities in your software. Visit Vulert Scanner to check if your application is affected by this vulnerability.
Yes, a patch is available. Users should update their Linux kernel to the latest version to mitigate this vulnerability.
The urgency for this vulnerability has not yet been assigned, but it is advisable to apply the patch as soon as it becomes available.
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