CVE-2021-47235 net: ethernet: fix potential use-after-free in ec_bhf_remove

What is CVE-2021-47235?

CVE-2021-47235 is a high-severity use after free vulnerability in Linux kernel, published on 21 May 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: ethernet: fix potential use-after-free in ec_bhf_remove

static void ec_bhf_remove(struct pci_dev *dev) { ... struct ec_bhf_priv *priv = netdev_priv(net_dev);

unregister_netdev(net_dev); free_netdev(net_dev);

pci_iounmap(dev, priv->dma_io); pci_iounmap(dev, priv->io); ... }

priv is netdev private data, but it is used after free_netdev(). It can cause use-after-free when accessing priv pointer. So, fix it by moving free_netdev() after pci_iounmap() calls.

Weakness: CWE-416

Which versions are affected by CVE-2021-47235?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2021-47235?

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-2021-47235 being exploited?

There is no known exploitation of CVE-2021-47235 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-2021-47235, GHSA-pcr5-v468-562j, UBUNTU-CVE-2021-47235.