CVE-2021-47613 i2c: virtio: fix completion handling

What is CVE-2021-47613?

CVE-2021-47613 is a high-severity vulnerability in Linux kernel, published on 19 Jun 2024.

Official description

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

i2c: virtio: fix completion handling

The driver currently assumes that the notify callback is only received when the device is done with all the queued buffers.

However, this is not true, since the notify callback could be called without any of the queued buffers being completed (for example, with virtio-pci and shared interrupts) or with only some of the buffers being completed (since the driver makes them available to the device in multiple separate virtqueue_add_sgs() calls).

This can lead to incorrect data on the I2C bus or memory corruption in the guest if the device operates on buffers which are have been freed by the driver. (The WARN_ON in the driver is also triggered.)

BUG kmalloc-128 (Tainted: G W ): Poison overwritten First byte 0x0 instead of 0x6b Allocated in i2cdev_ioctl_rdwr+0x9d/0x1de age=243 cpu=0 pid=28 memdup_user+0x2e/0xbd i2cdev_ioctl_rdwr+0x9d/0x1de i2cdev_ioctl+0x247/0x2ed vfs_ioctl+0x21/0x30 sys_ioctl+0xb18/0xb41 Freed in i2cdev_ioctl_rdwr+0x1bb/0x1de age=68 cpu=0 pid=28 kfree+0x1bd/0x1cc i2cdev_ioctl_rdwr+0x1bb/0x1de i2cdev_ioctl+0x247/0x2ed vfs_ioctl+0x21/0x30 sys_ioctl+0xb18/0xb41

Fix this by calling virtio_get_buf() from the notify handler like other virtio drivers and by actually waiting for all the buffers to be completed.

Which versions are affected by CVE-2021-47613?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2021-47613?

Upgrade to a fixed version.

Is CVE-2021-47613 being exploited?

There is no known exploitation of CVE-2021-47613 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-2021-47613, GHSA-xpr2-p5g8-h7fq, UBUNTU-CVE-2021-47613.