Network Bridge Vulnerability in Linux Kernel

CVE-2026-98881

What is CVE-2026-98881?

In the Linux kernel, a vulnerability was identified in the network bridge subsystem, specifically in the handling of multicast device deletions. The issue arose from the presence of a residual rcu_barrier() that created excessive Real-Time Networking Layer (RTNL) pressure, leading to potential blocking of tasks. The problematic rcu_barrier() was retained from earlier implementations involving call_rcu(). With the transition to kfree_rcu(), this barrier was deemed unnecessary and was subsequently removed, improving both performance and stability of network operations. This fix addresses the underlying concerns highlighted in various syzbot reports, enhancing the overall responsiveness of the Linux kernel's networking stack.

References