Race Condition Vulnerability in Linux Kernel - Impacting Debian Packages
Summary
CVE-2025-38477: In the Linux kernel, the following vulnerability has been resolved: net/sched: sch_qfq: Fix race condition on qfq_aggregate A race condition can occur when 'agg' is modified in qfq_change_agg (called during qfq_enqueue)... 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 the core component of the Debian operating system, responsible for managing hardware and system resources. It provides essential services for all other software running on the system. The kernel is designed to be robust and secure, but vulnerabilities can arise, such as the one identified in CVE-2025-38477, which affects multiple Debian versions (11, 12, and 13). This vulnerability can lead to critical system instability and security issues if not addressed promptly.
Vulnerability Detail
CVE-2025-38477 is a race condition vulnerability found in the Linux kernel's network scheduler, specifically within the 'sch_qfq' (Classful Fair Queueing) component. The issue arises when the 'agg' structure is modified during concurrent access by multiple threads. This can lead to a NULL dereference in the qfq_dump_class function and a use-after-free condition in the qfq_delete_class function. Such vulnerabilities can be exploited to crash the system or execute arbitrary code, posing significant risks to system integrity and security.
How To Fix
No fixed version is published for this vulnerability.
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Workaround
As a temporary workaround, you can limit the number of concurrent threads accessing the qfq_aggregate function. However, this is not a permanent solution and should only be used until the patch is applied.
Conclusion
CVE-2025-38477 is a critical race condition vulnerability in the Linux kernel affecting multiple Debian versions. It is essential to apply the available patches to mitigate the risks associated with this vulnerability. Users are encouraged to monitor their systems and utilize tools like Vulert for real-time vulnerability alerts.
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FAQ
CVE-2025-38477 is a race condition vulnerability in the Linux kernel that affects the Classful Fair Queueing component, potentially leading to system crashes or arbitrary code execution.
The vulnerability affects Debian versions 11, 12, and 13.
You can use the Vulert platform to monitor and alert for open-source vulnerabilities in your software. Check your application against the vulnerability using the Vulert playground at Vulert Scanner.
If immediate updates are not possible, consider implementing a temporary workaround by limiting concurrent access to the affected functions until the patch can be applied.
This vulnerability is considered serious as it can lead to system instability and potential exploitation by attackers, making it crucial to apply the patch as soon as possible.
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