CVE-2022-4696

Published: 11 January 2023

There exists a use-after-free vulnerability in the Linux kernel through io_uring and the IORING_OP_SPLICE operation. If IORING_OP_SPLICE is missing the IO_WQ_WORK_FILES flag, which signals that the operation won't use current->nsproxy, so its reference counter is not increased. This assumption is not always true as calling io_splice on specific files will call the get_uts function which will use current->nsproxy leading to invalidly decreasing its reference counter later causing the use-after-free vulnerability. We recommend upgrading to version 5.10.160 or above

From the Ubuntu Security Team

It was discovered that a use-after-free vulnerability existed in the io_uring subsystem in the Linux kernel. A local attacker could possibly use this to cause a denial of service (system crash) or possibly execute arbitrary code.

Status

Severity score breakdown

References

• https://kernel.dance/#75454b4bbfc7e6a4dd8338556f36ea9107ddf61a
• https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=linux-5.10.y&id=75454b4bbfc7e6a4dd8338556f36ea9107ddf61a
• https://www.cve.org/CVERecord?id=CVE-2022-4696
• NVD
• Launchpad
• Debian