Linux Kernel up to 5.4.123/5.10.41/5.12.8 TIPC sock_release denial of service

Summaryinfo

A vulnerability classified as very critical has been found in Linux Kernel up to 5.4.123/5.10.41/5.12.8. This affects the function sock_release of the component TIPC Module. The manipulation leads to denial of service. This vulnerability is uniquely identified as CVE-2021-47163. No exploit exists. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability was found in Linux Kernel up to 5.4.123/5.10.41/5.12.8 and classified as critical. This issue affects the function sock_release of the component TIPC Module. The manipulation with an unknown input leads to a denial of service vulnerability. Using CWE to declare the problem leads to CWE-404. The product does not release or incorrectly releases a resource before it is made available for re-use. Impacted is availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: tipc: wait and exit until all work queues are done On some host, a crash could be triggered simply by repeating these commands several times: # modprobe tipc # tipc bearer enable media udp name UDP1 localip 127.0.0.1 # rmmod tipc [] BUG: unable to handle kernel paging request at ffffffffc096bb00 [] Workqueue: events 0xffffffffc096bb00 [] Call Trace: [] ? process_one_work+0x1a7/0x360 [] ? worker_thread+0x30/0x390 [] ? create_worker+0x1a0/0x1a0 [] ? kthread+0x116/0x130 [] ? kthread_flush_work_fn+0x10/0x10 [] ? ret_from_fork+0x35/0x40 When removing the TIPC module, the UDP tunnel sock will be delayed to release in a work queue as sock_release() can't be done in rtnl_lock(). If the work queue is schedule to run after the TIPC module is removed, kernel will crash as the work queue function cleanup_beareri() code no longer exists when trying to invoke it. To fix it, this patch introduce a member wq_count in tipc_net to track the numbers of work queues in schedule, and wait and exit until all work queues are done in tipc_exit_net().

The advisory is shared at git.kernel.org. The identification of this vulnerability is CVE-2021-47163. The exploitation is known to be easy. Technical details are known, but no exploit is available. The price for an exploit might be around USD $0-$5k at the moment (estimation calculated on 08/04/2025).

We expect the 0-day to have been worth approximately . The vulnerability scanner Nessus provides a plugin with the ID 212567 (SUSE SLES12 Security Update : kernel (SUSE-SU-2024:4100-1)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 5.4.124, 5.10.42, 5.12.9 or 5.13 eliminates this vulnerability. Applying the patch d1f76dfadaf8/5195ec5e365a/b9f5b7ad4ac3/04c26faa51d1 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 (212567) and CERT Bund (WID-SEC-2024-0699). If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Affected

• Amazon Linux 2
• Red Hat Enterprise Linux
• Ubuntu Linux
• SUSE Linux
• Oracle Linux
• EMC Avamar
• Dell NetWorker
• Open Source Linux Kernel
• IBM Spectrum Protect Plus

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 5.4.123
• 5.10.0
• 5.10.1
• 5.10.2
• 5.10.3
• 5.10.4
• 5.10.5
• 5.10.6
• 5.10.7
• 5.10.8
• 5.10.9
• 5.10.10
• 5.10.11
• 5.10.12
• 5.10.13
• 5.10.14
• 5.10.15
• 5.10.16
• 5.10.17
• 5.10.18
• 5.10.19
• 5.10.20
• 5.10.21
• 5.10.22
• 5.10.23
• 5.10.24
• 5.10.25
• 5.10.26
• 5.10.27
• 5.10.28
• 5.10.29
• 5.10.30
• 5.10.31
• 5.10.32
• 5.10.33
• 5.10.34
• 5.10.35
• 5.10.36
• 5.10.37
• 5.10.38
• 5.10.39
• 5.10.40
• 5.10.41
• 5.12.0
• 5.12.1
• 5.12.2
• 5.12.3
• 5.12.4
• 5.12.5
• 5.12.6
• 5.12.7
• 5.12.8

License

• open-source

Website

• Vendor: https://www.kernel.org/

CPE 2.3info

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CPE 2.2info

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Exploitinginfo

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Entryinfo

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