CVE-2022-3176: Use-after-free in io_uring in Linux Kernel

Vulnerability summary

CVE-2022-3176 is a high (CVSS 7.8) Use After Free vulnerability in debian debian_linux. EPSS estimates a 0.30% chance of exploitation in the next 30 days, higher than 22.7% of scored vulnerabilities.

Timeline

1. 16-09-2022
   PublishedVulnerability first disclosed.
2. 21-04-2025
   Last modifiedVulnerability information updated.

Description

There exists a use-after-free in io_uring in the Linux kernel. Signalfd_poll() and binder_poll() use a waitqueue whose lifetime is the current task. It will send a POLLFREE notification to all waiters before the queue is freed. Unfortunately, the io_uring poll doesn't handle POLLFREE. This allows a use-after-free to occur if a signalfd or binder fd is polled with io_uring poll, and the waitqueue gets freed. We recommend upgrading past commit fc78b2fc21f10c4c9c4d5d659a685710ffa63659

• CWE-416Use After FreeThe product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.