CVE-2021-47613

CVE-2021-47613 is a high-severity vulnerability in Linux Linux Kernel with a CVSS 3.x base score of 7.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

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.

Frequently asked questions

What is CVE-2021-47613?
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.
How severe is CVE-2021-47613?
CVE-2021-47613 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-47613 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (12th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-47613?
CVE-2021-47613 primarily affects Linux Linux Kernel. In total, 5 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-47613?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2021-47613 have an EU (EUVD) identifier?
Yes. CVE-2021-47613 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2021-34615.
When was CVE-2021-47613 published?
CVE-2021-47613 was published on 2024-06-19 and last updated on 2026-06-17.

References

Affected products (5)

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