Kernel Vulnerability in Linux Packages: UAF Issue in Event Trigger Handling
Summary
CVE-2025-21899: In the Linux kernel, the following vulnerability has been resolved: tracing: Fix bad hist from corrupting named_triggers list The following commands causes a crash: ~# cd /sys/kernel/tracing/events/rcu/rcu_callback ~# ec... 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 many operating systems, providing essential services for hardware and software interactions. It is known for its stability, performance, and security features. However, vulnerabilities can arise, impacting system integrity and performance. This specific vulnerability affects the event trigger handling mechanism within the kernel, which is crucial for managing events and actions in response to system activities.
Vulnerability Detail
In the Linux kernel, a vulnerability has been identified that leads to a use-after-free (UAF) condition in the event trigger handling mechanism. This issue arises when a trigger is registered but not properly added to the list of active triggers, leading to a situation where the memory allocated for the trigger can be freed while still being referenced. If a new trigger with the same name is registered afterward, it can cause the kernel to crash due to accessing freed memory. The vulnerability is triggered by specific commands that manipulate event triggers, resulting in potential system instability and crashes.
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. It is advisable to avoid using the commands that trigger the vulnerability until a patch is applied.
Conclusion
The identified vulnerability in the Linux kernel poses a significant risk due to its potential to cause system crashes through improper event trigger handling. Users are encouraged to update their systems to the patched version to mitigate this risk and ensure system stability.
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FAQ
The vulnerability is a use-after-free (UAF) issue in the Linux kernel's event trigger handling, which can lead to system crashes.
The vulnerability affects Linux packages across Debian 11, 12, and 13, with a specific fix available for Debian 13.
You can use tools like Vulert to monitor and alert for open-source vulnerabilities in your software. Visit Vulert Scanner to check your application without needing to sign up.
If immediate updates are not possible, avoid using the commands that trigger the vulnerability until a patch is applied.
More information can be found in the official CVE database or through security advisories related to the Linux kernel.
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