CVE-2026-43481: Kernel Memory Corruption in Linux Kernel

The core of the vulnerability lies in the improper handling of SKBs (socket kernel buffers) within the net-shapers network shaping functionality. After genlmsgreply() is called, the reply SKB is intended to be consumed by netlink on all return paths. However, the netshapernlgetdoit() and netshapernlcapgetdoit() functions prematurely call nlmsgfree(msg) after a genlmsgreply() failure, leading to a double free. This double free can corrupt memory, potentially allowing an attacker to trigger a denial-of-service by crashing the kernel or gaining limited control over system resources. While direct code execution is unlikely, the DoS impact can be significant, disrupting network services and potentially leading to system downtime. The blast radius extends to any system relying on the affected kernel version for network shaping or traffic management.

1. Reserviert2026-05-01
2. Veröffentlicht2026-05-13
3. EPSS aktualisiert2026-05-14

The primary mitigation for CVE-2026-43481 is to upgrade the Linux Kernel to version 57885276cc16a2e2b76282c808a4e84cbecb3aae or later. If an immediate upgrade is not feasible due to compatibility concerns or testing requirements, consider implementing temporary workarounds. While no direct WAF or proxy rules can prevent this kernel-level vulnerability, restricting access to the netlink interface used by net-shapers could reduce the attack surface. Monitor system logs for unusual memory allocation patterns or kernel panics, which could indicate exploitation attempts. Review and audit any custom network shaping configurations to ensure they adhere to best practices and minimize potential vulnerabilities. After upgrading, confirm the fix by verifying the kernel version using uname -r and ensuring it is greater than or equal to 57885276cc16a2e2b76282c808a4e84cbecb3aae.