CVE-2021-47596 net: hns3: fix use-after-free bug in hclgevf_send_mbx_msg

What is CVE-2021-47596?

CVE-2021-47596 is a high-severity use after free vulnerability in Linux kernel, published on 19 Jun 2024. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

In the Linux kernel, the following vulnerability has been resolved:

net: hns3: fix use-after-free bug in hclgevf_send_mbx_msg

Currently, the hns3_remove function firstly uninstall client instance, and then uninstall acceletion engine device. The netdevice is freed in client instance uninstall process, but acceletion engine device uninstall process still use it to trace runtime information. This causes a use after free problem.

So fixes it by check the instance register state to avoid use after free.

Weakness: CWE-416

Which versions are affected by CVE-2021-47596?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2021-47596?

Apply the vendor's patch.

Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.

Is CVE-2021-47596 being exploited?

There is no known exploitation of CVE-2021-47596 in the wild and no public exploit code.

Other vulnerabilities in Linux kernel

• CVE-2026-53266 Linux Kernel Out-of-Bounds Write Exploited High 8.8
• CVE-2013-6282 Linux Kernel Improper Input Validation Exploited High 8.8
• CVE-2022-0185 Linux Kernel Heap-Based Buffer Overflow Exploited High 8.4
• CVE-2013-2094 Linux Kernel Privilege Escalation Exploited High 8.4
• CVE-2026-53362 Linux Kernel Unspecified Exploited High 7.8

All Linux kernel vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as DEBIAN-CVE-2021-47596, GHSA-5xg5-ffcr-c2cc, UBUNTU-CVE-2021-47596.