RCU Protection Vulnerability in Linux Kernel: CVE-2025-21758
Summary
CVE-2025-21758: In the Linux kernel, the following vulnerability has been resolved: ipv6: mcast: add RCU protection to mld_newpack() mld_newpack() can be called without RTNL or RCU being held. 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, such as CVE-2025-21758, which affects the IPv6 multicast handling, specifically in the mld_newpack() function. This vulnerability can lead to potential security risks if not addressed promptly.
Vulnerability Detail
CVE-2025-21758 is a vulnerability in the Linux kernel's IPv6 multicast handling, where the mld_newpack() function can be called without proper RCU (Read-Copy-Update) protection. This oversight can lead to race conditions and unpredictable behavior, potentially allowing unauthorized access or denial of service. The issue arises because the function does not hold the necessary RTNL (Routing Netlink) or RCU locks, which are crucial for maintaining data integrity during concurrent operations.
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. The best course of action is to apply the patch by updating the kernel as described in the 'how_to_fix' section.
Conclusion
CVE-2025-21758 is a significant vulnerability in the Linux kernel that requires immediate attention. Users are advised to update their systems to the latest patched version to mitigate potential risks. Utilizing tools like Vulert can help monitor for such vulnerabilities in real-time.
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FAQ
CVE-2025-21758 is a vulnerability in the Linux kernel related to improper handling of IPv6 multicast, which can lead to security risks.
You can use tools like Vulert to monitor and alert for open-source vulnerabilities in your software. Visit Vulert Scanner to check if your application is affected.
If exploited, this vulnerability could lead to race conditions, unauthorized access, or denial of service in systems using the affected kernel versions.
Yes, a patch is available. Users should update their Linux kernel to the latest version that addresses CVE-2025-21758.
RCU (Read-Copy-Update) protection is a synchronization mechanism that allows safe access to shared data in concurrent programming, preventing data corruption and ensuring system stability.
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