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🛡️ CVE-2023-53366 — kernel

🟡 CVSS 5.5 — Medium ✅ No Known Exploit NVD
5.5
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

block: be a bit more careful in checking for NULL bdev while polling

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.

How this vulnerability can be exploited

This issue can be reached with local access to the system, attack complexity is low, an attacker needs low-level privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality none, integrity none, availability high.

CVSS metrics in full

The score comes from this vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

  • Attack vector: Local — a local account, shell or session on the host is needed.
  • Attack complexity: Low — the attack works reliably, with no preparation.
  • Privileges required: Low — an ordinary user account is enough.
  • User interaction: None — nobody has to be tricked into anything.
  • Scope: Unchanged — the damage stays inside the vulnerable component.
  • Confidentiality impact: None.
  • Integrity impact: None.
  • Availability impact: High — total loss, or loss the attacker controls.

Affected software

CVE-2023-53366 is recorded against 2 packages.

  • kernel (from 6.2.0 up to 6.2.3)
  • linux-kernel (from 6.2 up to 6.2.3)

Timeline and source

Published on 17 September 2025 and last revised on 12 August 2026. No public exploit is currently recorded for this entry. A vendor advisory or fix has been published. Record sourced from NVD.

References

git.kernel.org (Web)
git.kernel.org (Web)
git.kernel.org (Web)
github.com (Advisory)
nvd.nist.gov (Advisory)
git.kernel.org (Package)

Other advisories for this package

kernel has other advisories on record. If you are patching this one, these are worth checking on the same host:

CVE-2023-53366 on other distributions

Each distribution ships its own build and its own fixed version. Pick the one you run:

Details

Severity Medium
CVSS Score 5.5
CVSS Vector CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
CWE N/A
Public Exploit ✅ No
Source NVD
Published 2025-09-17
Updated 2026-08-20
Modified 2026-08-12

Affected Packages

Software From version Fixed in
kernel 6.2.0 6.2.3
linux-kernel 6.2 6.2.3

Similar Threats

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ⓘ Data Notice: The information presented above has been compiled from publicly available internet sources. Boteraser aggregates this data solely for informational purposes and does not independently classify, evaluate, or endorse any findings about the vulnerabilities listed. The accuracy and completeness of this information is the sole responsibility of the original publishers. Boteraser and its operators accept no liability for any decisions made based on this data.

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