# CVE-2023-52903: linux: In the Linux kernel, the following vulnerability has been resolved:  io_uring: lock overflowing for IOPOLL  syzbot re...

CVE-2023-52903 is fixed in linux on 1 platform, first by DEBIAN-CVE-2023-52903, released August 21, 2024. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2023-52903
- Priority: Routine
- CVSS: 5.5 (medium)
- EPSS: 0.0019
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Aug 21, 2024

## Description

In the Linux kernel, the following vulnerability has been resolved:  io_uring: lock overflowing for IOPOLL  syzbot reports an issue with overflow filling for IOPOLL:  WARNING: CPU: 0 PID: 28 at io_uring/io_uring.c:734 io_cqring_event_overflow+0x1c0/0x230 io_uring/io_uring.c:734 CPU: 0 PID: 28 Comm: kworker/u4:1 Not tainted 6.2.0-rc3-syzkaller-16369-g358a161a6a9e #0 Workqueue: events_unbound io_ring_exit_work Call trace:  io_cqring_event_overflow+0x1c0/0x230 io_uring/io_uring.c:734  io_req_cqe_overflow+0x5c/0x70 io_uring/io_uring.c:773  io_fill_cqe_req io_uring/io_uring.h:168 [inline]  io_do_iopoll+0x474/0x62c io_uring/rw.c:1065  io_iopoll_try_reap_events+0x6c/0x108 io_uring/io_uring.c:1513  io_uring_try_cancel_requests+0x13c/0x258 io_uring/io_uring.c:3056  io_ring_exit_work+0xec/0x390 io_uring/io_uring.c:2869  process_one_work+0x2d8/0x504 kernel/workqueue.c:2289  worker_thread+0x340/0x610 kernel/workqueue.c:2436  kthread+0x12c/0x158 kernel/kthread.c:376  ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:863  There is no real problem for normal IOPOLL as flush is also called with uring_lock taken, but it's getting more complicated for IOPOLL|SQPOLL, for which __io_cqring_overflow_flush() happens from the CQ waiting path.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 12.15 (bookworm) | 6.1.7-1 | [DEBIAN-CVE-2023-52903](https://patchblox.com/security/data/fix/linux/debian-cve-2023-52903.md) | Aug 21, 2024 |
| Linux | linux Debian 13.5 (trixie) | 6.1.7-1 | [DEBIAN-CVE-2023-52903](https://patchblox.com/security/data/fix/linux/debian-cve-2023-52903.md) | Aug 21, 2024 |
| Linux | linux Debian 14 | 6.1.7-1 | [DEBIAN-CVE-2023-52903](https://patchblox.com/security/data/fix/linux/debian-cve-2023-52903.md) | Aug 21, 2024 |

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