Linux aws: In the Linux kernel, the following vulnerability has been resolved: ixgbevf: fix use-after-free in VEPA multicast source pruning… (CVE-2026-64113)

The Linux kernel's ixgbevf driver contained a use-after-free vulnerability in the VEPA multicast source pruning logic within the ixgbevf_clean_rx_irq() function. The skb pointer, declared outside a while loop, is freed and then not reset before continuing the loop, causing subsequent iterations to dereference a freed pointer. This leads to a use-after-free in NAPI softirq context. The issue was discovered by static analysis tools and corrected by applying the same pointer reset pattern used in the sibling iavf driver. The vulnerability affects multiple linux-aws kernel versions prior to 5.15.0-1112.119~20.04.1 and related versions. A patch is available and included in Ubuntu security updates USN-8575-1 and USN-8576-1, which address this and other kernel vulnerabilities.

Successful exploitation of this use-after-free vulnerability could lead to system instability, crashes, or potentially allow an attacker to execute arbitrary code with kernel privileges, given the high CVSS score (9.8) indicating high confidentiality, integrity, and availability impact. However, no known exploits in the wild have been reported. The vulnerability affects the Linux kernel's network driver handling VEPA multicast frames, which could be triggered by crafted network traffic.

A patch is available and has been released by Ubuntu as part of their Linux kernel security updates (USN-8575-1 and USN-8576-1). Users should apply the latest kernel updates for linux-aws and related packages and reboot their systems to ensure the fix is applied. Due to an ABI change, recompilation and reinstallation of third-party kernel modules may be required. No additional mitigation steps are indicated by the vendor advisory.