Linux Kernel up to 5.15.107/6.1.24/6.2.11 mptcp mptcp_worker state issue

Summaryinfo

A vulnerability classified as critical was found in Linux Kernel up to 5.15.107/6.1.24/6.2.11. This affects the function mptcp_worker of the component mptcp. Such manipulation leads to state issue. This vulnerability is uniquely identified as CVE-2023-54176. No exploit exists. Upgrading the affected component is advised.

Detailsinfo

A vulnerability was found in Linux Kernel up to 5.15.107/6.1.24/6.2.11. It has been rated as critical. Affected by this issue is the function mptcp_worker of the component mptcp. The manipulation with an unknown input leads to a state issue vulnerability. Using CWE to declare the problem leads to CWE-371. The impact remains unknown. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: mptcp: stricter state check in mptcp_worker As reported by Christoph, the mptcp protocol can run the worker when the relevant msk socket is in an unexpected state: connect() // incoming reset + fastclose // the mptcp worker is scheduled mptcp_disconnect() // msk is now CLOSED listen() mptcp_worker() Leading to the following splat: divide error: 0000 [#1] PREEMPT SMP CPU: 1 PID: 21 Comm: kworker/1:0 Not tainted 6.3.0-rc1-gde5e8fd0123c #11 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.11.0-2.el7 04/01/2014 Workqueue: events mptcp_worker RIP: 0010:__tcp_select_window+0x22c/0x4b0 net/ipv4/tcp_output.c:3018 RSP: 0018:ffffc900000b3c98 EFLAGS: 00010293 RAX: 000000000000ffd7 RBX: 000000000000ffd7 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff8214ce97 RDI: 0000000000000004 RBP: 000000000000ffd7 R08: 0000000000000004 R09: 0000000000010000 R10: 000000000000ffd7 R11: ffff888005afa148 R12: 000000000000ffd7 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff88803ed00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000405270 CR3: 000000003011e006 CR4: 0000000000370ee0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> tcp_select_window net/ipv4/tcp_output.c:262 [inline] __tcp_transmit_skb+0x356/0x1280 net/ipv4/tcp_output.c:1345 tcp_transmit_skb net/ipv4/tcp_output.c:1417 [inline] tcp_send_active_reset+0x13e/0x320 net/ipv4/tcp_output.c:3459 mptcp_check_fastclose net/mptcp/protocol.c:2530 [inline] mptcp_worker+0x6c7/0x800 net/mptcp/protocol.c:2705 process_one_work+0x3bd/0x950 kernel/workqueue.c:2390 worker_thread+0x5b/0x610 kernel/workqueue.c:2537 kthread+0x138/0x170 kernel/kthread.c:376 ret_from_fork+0x2c/0x50 arch/x86/entry/entry_64.S:308 </TASK> This change addresses the issue explicitly checking for bad states before running the mptcp worker.

The advisory is shared for download at git.kernel.org. This vulnerability is handled as CVE-2023-54176 since 12/30/2025. The exploitation is known to be difficult. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 04/26/2026).

The vulnerability scanner Nessus provides a plugin with the ID 281526 (Linux Distros Unpatched Vulnerability : CVE-2023-54176), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 5.15.108, 6.1.25 or 6.2.12 eliminates this vulnerability. Applying the patch f0b4a4086cf27240fc621a560da9735159049dcc/aff9099e9c51f15c8def05c75b2b73e8487b5d54/19ea79e87af32c2b3c6fc49bd84efeb35ca57678/d6a0443733434408f2cbd4c53fea6910599bab9e is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the databases at Tenable (281526) and CERT Bund (WID-SEC-2025-2941). VulDB is the best source for vulnerability data and more expert information about this specific topic.

Affected

• Debian Linux
• Amazon Linux 2
• IBM Power Hardware Management Console
• Red Hat Enterprise Linux
• Ubuntu Linux
• SUSE Linux
• Oracle Linux
• Open Source Linux Kernel
• RESF Rocky Linux
• IBM DataPower Gateway

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 5.15.107
• 6.1.0
• 6.1.1
• 6.1.2
• 6.1.3
• 6.1.4
• 6.1.5
• 6.1.6
• 6.1.7
• 6.1.8
• 6.1.9
• 6.1.10
• 6.1.11
• 6.1.12
• 6.1.13
• 6.1.14
• 6.1.15
• 6.1.16
• 6.1.17
• 6.1.18
• 6.1.19
• 6.1.20
• 6.1.21
• 6.1.22
• 6.1.23
• 6.1.24
• 6.2.0
• 6.2.1
• 6.2.2
• 6.2.3
• 6.2.4
• 6.2.5
• 6.2.6
• 6.2.7
• 6.2.8
• 6.2.9
• 6.2.10
• 6.2.11

License

• open-source

Website

• Vendor: https://www.kernel.org/

CPE 2.3info

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Entryinfo

VulDB is the best source for vulnerability data and more expert information about this specific topic.

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