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🛡️ CVE-2023-53072 — kernel

🟠 CVSS 7.8 — High ✅ No Known Exploit NVD
7.8
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

mptcp: use the workqueue to destroy unaccepted sockets

In the Linux kernel, the following vulnerability has been resolved:

mptcp: use the workqueue to destroy unaccepted sockets

Christoph reported a UaF at token lookup time after having

refactored the passive socket initialization part:

BUG: KASAN: use-after-free in __token_bucket_busy+0x253/0x260

Read of size 4 at addr ffff88810698d5b0 by task syz-executor653/3198

CPU: 1 PID: 3198 Comm: syz-executor653 Not tainted 6.2.0-rc59af4eaa31c1f6c00c8f1e448ed99a45c66340dd5 #6

Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014

Call Trace:

<TASK>

dump_stack_lvl+0x6e/0x91

print_report+0x16a/0x46f

kasan_report+0xad/0x130

__token_bucket_busy+0x253/0x260

mptcp_token_new_connect+0x13d/0x490

mptcp_connect+0x4ed/0x860

__inet_stream_connect+0x80e/0xd90

tcp_sendmsg_fastopen+0x3ce/0x710

mptcp_sendmsg+0xff1/0x1a20

inet_sendmsg+0x11d/0x140

__sys_sendto+0x405/0x490

__x64_sys_sendto+0xdc/0x1b0

do_syscall_64+0x3b/0x90

entry_SYSCALL_64_after_hwframe+0x72/0xdc

We need to properly clean-up all the paired MPTCP-level

resources and be sure to release the msk last, even when

the unaccepted subflow is destroyed by the TCP internals

via inet_child_forget().

We can re-use the existing MPTCP_WORK_CLOSE_SUBFLOW infra,

explicitly checking that for the critical scenario: the

closed subflow is the MPC one, the msk is not accepted and

eventually going through full cleanup.

With such change, __mptcp_destroy_sock() is always called

on msk sockets, even on accepted ones. We don't need anymore

to transiently drop one sk reference at msk clone time.

Please note this commit depends on the parent one:

mptcp: refactor passive socket initialization

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 high, integrity high, 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:H/I:H/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: High — total loss, or loss the attacker controls.
  • Integrity impact: High — total loss, or loss the attacker controls.
  • Availability impact: High — total loss, or loss the attacker controls.

Affected software

CVE-2023-53072 is recorded against 2 packages.

  • kernel (from 6.2.0 up to 6.2.8)
  • linux-kernel

Timeline and source

Published on 2 May 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:

Details

Severity High
CVSS Score 7.8
CVSS Vector CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CWE N/A
Public Exploit ✅ No
Source NVD
Published 2025-05-02
Updated 2026-08-20
Modified 2026-08-12

Affected Packages

Software From version Fixed in
kernel 6.2.0 6.2.8
linux-kernel — —

Similar Threats

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