CVE-2023-53366: linux kernel Null Dereference — Fix

Description

In the Linux kernel, the following vulnerability has been resolved: block: be a bit more careful in checking for NULL bdev while polling Wei reports a crash with an application using polled IO: PGD 14265e067 P4D 14265e067 PUD 47ec50067 PMD 0 Oops: 0000 [#1] SMP CPU: 0 PID: 21915 Comm: iocore_0 Kdump: loaded Tainted: G S 5.12.0-0_fbk12_clang_7346_g1bb6f2e7058f #1 Hardware name: Wiwynn Delta Lake MP T8/Delta Lake-Class2, BIOS Y3DLM08 04/10/2022 RIP: 0010:bio_poll+0x25/0x200 Code: 0f 1f 44 00 00 0f 1f 44 00 00 55 41 57 41 56 41 55 41 54 53 48 83 ec 28 65 48 8b 04 25 28 00 00 00 48 89 44 24 20 48 8b 47 08 <48> 8b 80 70 02 00 00 4c 8b 70 50 8b 6f 34 31 db 83 fd ff 75 25 65 RSP: 0018:ffffc90005fafdf8 EFLAGS: 00010292 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 74b43cd65dd66600 RDX: 0000000000000003 RSI: ffffc90005fafe78 RDI: ffff8884b614e140 RBP: ffff88849964df78 R08: 0000000000000000 R09: 0000000000000008 R10: 0000000000000000 R11: 0000000000000000 R12: ffff88849964df00 R13: ffffc90005fafe78 R14: ffff888137d3c378 R15: 0000000000000001 FS: 00007fd195000640(0000) GS:ffff88903f400000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000270 CR3: 0000000466121001 CR4: 00000000007706f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 PKRU: 55555554 Call Trace: iocb_bio_iopoll+0x1d/0x30 io_do_iopoll+0xac/0x250 __se_sys_io_uring_enter+0x3c5/0x5a0 ? __x64_sys_write+0x89/0xd0 do_syscall_64+0x2d/0x40 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x94f225d Code: 24 cc 00 00 00 41 8b 84 24 d0 00 00 00 c1 e0 04 83 e0 10 41 09 c2 8b 33 8b 53 04 4c 8b 43 18 4c 63 4b 0c b8 aa 01 00 00 0f 05 <85> c0 0f 88 85 00 00 00 29 03 45 84 f6 0f 84 88 00 00 00 41 f6 c7 RSP: 002b:00007fd194ffcd88 EFLAGS: 00000202 ORIG_RAX: 00000000000001aa RAX: ffffffffffffffda RBX: 00007fd194ffcdc0 RCX: 00000000094f225d RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000007 RBP: 00007fd194ffcdb0 R08: 0000000000000000 R09: 0000000000000008 R10: 0000000000000001 R11: 0000000000000202 R12: 00007fd269d68030 R13: 0000000000000000 R14: 0000000000000001 R15: 0000000000000000 which is due to bio->bi_bdev being NULL. This can happen if we have two tasks doing polled IO, and task B ends up completing IO from task A if they are sharing a poll queue. If task B completes the IO and puts the bio into our cache, then it can allocate that bio again before task A is done polling for it. As that would necessitate a preempt between the two tasks, it's enough to just be a bit more careful in checking for whether or not bio->bi_bdev is NULL.

Is your site exposed to CVE-2023-53366?

Run a free security scan — no signup, results in seconds.

CVSS v3.1 Score

5.5

MEDIUM

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Weakness Type (CWE)

CWE-476 CWE-476

Affected Products

Vendor	Product	Versions
linux	linux_kernel	5.15 — 6.1.16
linux	linux_kernel	6.2 — 6.2.3

References

Advisories & Patches

https://git.kernel.org/stable/c/0510d5e654d05053ed0e6309a9b42043ac9903ab https://git.kernel.org/stable/c/1af0bdca03f367874da45d6cbe05fa05b90b1439 https://git.kernel.org/stable/c/310726c33ad76cebdee312dbfafc12c1b44bf977

Frequently Asked Questions

What is CVE-2023-53366? +

In the Linux kernel, the following vulnerability has been resolved: block: be a bit more careful in checking for NULL bdev while polling Wei reports a crash with an application using polled IO: PGD 14265e067 P4D 14265e067 PUD 47ec50067 PMD 0 Oops: 0000 [#1] SMP CPU: 0 PID: 21915 Comm: iocore_0 Kdump: loaded Tainted: G S 5.12.0-0_fbk12_clang_7346_g1bb6f2e7058f #1 Hardware name: Wiwynn Delta Lake MP T8/Delta Lake-Class2, BIOS Y3DLM08 04/10/2022 RIP: 0010:bio_poll+0x25/0x200 Code: 0f 1f 44 00 00 0f 1f 44 00 00 55 41 57 41 56 41 55 41 54 53 48 83 ec 28 65 48 8b 04 25 28 00 00 00 48 89 44 24 20 48 8b 47 08 <48> 8b 80 70 02 00 00 4c 8b 70 50 8b 6f 34 31 db 83 fd ff 75 25 65 RSP: 0018:ffffc90005fafdf8 EFLAGS: 00010292 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 74b43cd65dd66600 RDX: 0000000000000003 RSI: ffffc90005fafe78 RDI: ffff8884b614e140 RBP: ffff88849964df78 R08: 0000000000000000 R09: 0000000000000008 R10: 0000000000000000 R11: 0000000000000000 R12: ffff88849964df00 R13: ffffc90005fafe78 R14: ffff888137d3c378 R15: 0000000000000001 FS: 00007fd195000640(0000) GS:ffff88903f400000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000270 CR3: 0000000466121001 CR4: 00000000007706f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 PKRU: 55555554 Call Trace: iocb_bio_iopoll+0x1d/0x30 io_do_iopoll+0xac/0x250 __se_sys_io_uring_enter+0x3c5/0x5a0 ? __x64_sys_write+0x89/0xd0 do_syscall_64+0x2d/0x40 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x94f225d Code: 24 cc 00 00 00 41 8b 84 24 d0 00 00 00 c1 e0 04 83 e0 10 41 09 c2 8b 33 8b 53 04 4c 8b 43 18 4c 63 4b 0c b8 aa 01 00 00 0f 05 <85> c0 0f 88 85 00 00 00 29 03 45 84 f6 0f 84 88 00 00 00 41 f6 c7 RSP: 002b:00007fd194ffcd88 EFLAGS: 00000202 ORIG_RAX: 00000000000001aa RAX: ffffffffffffffda RBX: 00007fd194ffcdc0 RCX: 00000000094f225d RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000007 RBP: 00007fd194ffcdb0 R08: 0000000000000000 R09: 0000000000000008 R10: 0000000000000001 R11: 0000000000000202 R12: 00007fd269d68030 R13: 0000000000000000 R14: 0000000000000001 R15: 0000000000000000 which is due to bio->bi_bdev being NULL. This can happen if we have two tasks doing polled IO, and task B ends up completing IO from task A if they are sharing a poll queue. If task B completes the IO and puts the bio into our cache, then it can allocate that bio again before task A is done polling for it. As that would necessitate a preempt between the two tasks, it's enough to just be a bit more careful in checking for whether or not bio->bi_bdev is NULL. It has a CVSS v3.1 base score of 5.5 (MEDIUM).

How severe is CVE-2023-53366? +

CVE-2023-53366 has a CVSS v3.1 score of 5.5 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.

What products are affected by CVE-2023-53366? +

CVE-2023-53366 affects products from linux, specifically: linux_kernel. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2023-53366? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

Related Vulnerabilities

CVE-2026-8479

IEC 60870-5-104 used in bidirectional mode in RTU500 is vulnerable for a NULL pointer dereferencing, if a specially crafted sequence …

CVE-2025-24031

PAM-PKCS#11 is a Linux-PAM login module that allows a X.509 certificate based user login. In versions 0.6.12 and prior, the …

CVE-2025-31115

XZ Utils provide a general-purpose data-compression library plus command-line tools. In XZ Utils 5.3.3alpha to 5.8.0, the multithreaded .xz decoder …

CVE-2025-0121

A null pointer dereference vulnerability in the Palo Alto Networks Cortex® XDR agent on Windows devices allows a low-privileged local …

CVE-2023-45925

GNU Midnight Commander 4.8.29-146-g299d9a2fb was discovered to contain a NULL pointer dereference via the function x_error_handler() at tty/x11conn.c. NOTE: this …

CVE-2025-6398

A null pointer dereference vulnerability exists in the IOMap64.sys driver of ASUS AI Suite 3. The vulnerability can be triggered …

CVE-2023-53366