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
The 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 Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.
| Link | Tags |
|---|---|
| https://kernel.dance/#fc78b2fc21f10c4c9c4d5d659a685710ffa63659 | patch vendor advisory |
| https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit?h=linux-5.4.y&id=fc78b2fc21f10c4c9c4d5d659a685710ffa63659 | mailing list patch vendor advisory |
| https://www.debian.org/security/2022/dsa-5257 | third party advisory vendor advisory |
| https://lists.debian.org/debian-lts-announce/2022/11/msg00001.html | third party advisory mailing list |
| https://security.netapp.com/advisory/ntap-20230216-0003/ | third party advisory |