Linux Kernel up to 6.1.103/6.6.44/6.10.3 iucv_sock_close use after free

Summaryinfo

A vulnerability, which was classified as critical, has been found in Linux Kernel up to 6.1.103/6.6.44/6.10.3. The affected element is the function iucv_sock_close. This manipulation causes use after free. This vulnerability is tracked as CVE-2024-42271. No exploit exists. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability has been found in Linux Kernel up to 6.1.103/6.6.44/6.10.3 and classified as critical. Affected by this vulnerability is the function iucv_sock_close. The manipulation with an unknown input leads to a use after free vulnerability. The CWE definition for the vulnerability is CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: net/iucv: fix use after free in iucv_sock_close() iucv_sever_path() is called from process context and from bh context. iucv->path is used as indicator whether somebody else is taking care of severing the path (or it is already removed / never existed). This needs to be done with atomic compare and swap, otherwise there is a small window where iucv_sock_close() will try to work with a path that has already been severed and freed by iucv_callback_connrej() called by iucv_tasklet_fn(). Example: [452744.123844] Call Trace: [452744.123845] ([] 0x1e87f03880) [452744.123966] [] iucv_path_sever+0x96/0x138 [452744.124330] [] iucv_sever_path+0xc2/0xd0 [af_iucv] [452744.124336] [] iucv_sock_close+0xa6/0x310 [af_iucv] [452744.124341] [] iucv_sock_release+0x3c/0xd0 [af_iucv] [452744.124345] [] __sock_release+0x5e/0xe8 [452744.124815] [] sock_close+0x34/0x48 [452744.124820] [] __fput+0xba/0x268 [452744.124826] [] task_work_run+0xbc/0xf0 [452744.124832] [] do_notify_resume+0x88/0x90 [452744.124841] [] system_call+0xe2/0x2c8 [452744.125319] Last Breaking-Event-Address: [452744.125321] [] iucv_path_sever+0x90/0x138 [452744.125324] [452744.125325] Kernel panic - not syncing: Fatal exception in interrupt Note that bh_lock_sock() is not serializing the tasklet context against process context, because the check for sock_owned_by_user() and corresponding handling is missing. Ideas for a future clean-up patch: A) Correct usage of bh_lock_sock() in tasklet context, as described in Re-enqueue, if needed. This may require adding return values to the tasklet functions and thus changes to all users of iucv. B) Change iucv tasklet into worker and use only lock_sock() in af_iucv.

The advisory is shared at git.kernel.org. This vulnerability is known as CVE-2024-42271 since 07/30/2024. The exploitation appears to be difficult. 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 02/01/2026).

The vulnerability scanner Nessus provides a plugin with the ID 207884 (openSUSE 15 Security Update : kernel (SUSE-SU-2024:3483-1)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 6.1.104, 6.6.45 or 6.10.4 eliminates this vulnerability. Applying the patch 8b424c9e4411/01437282fd39/69620522c48c/f558120cd709 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 (207884) and CERT Bund (WID-SEC-2024-1875). Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Affected

• Debian Linux
• Amazon Linux 2
• Red Hat Enterprise Linux
• Ubuntu Linux
• SUSE Linux
• IBM InfoSphere Guardium
• Oracle Linux
• IBM Security Guardium
• RESF Rocky Linux
• Broadcom Brocade SANnav
• Open Source Linux Kernel
• IBM QRadar SIEM
• IBM Spectrum Protect Plus
• SolarWinds Security Event Manager
• IBM DataPower Gateway
• Dell NetWorker

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 6.1.103
• 6.6.0
• 6.6.1
• 6.6.2
• 6.6.3
• 6.6.4
• 6.6.5
• 6.6.6
• 6.6.7
• 6.6.8
• 6.6.9
• 6.6.10
• 6.6.11
• 6.6.12
• 6.6.13
• 6.6.14
• 6.6.15
• 6.6.16
• 6.6.17
• 6.6.18
• 6.6.19
• 6.6.20
• 6.6.21
• 6.6.22
• 6.6.23
• 6.6.24
• 6.6.25
• 6.6.26
• 6.6.27
• 6.6.28
• 6.6.29
• 6.6.30
• 6.6.31
• 6.6.32
• 6.6.33
• 6.6.34
• 6.6.35
• 6.6.36
• 6.6.37
• 6.6.38
• 6.6.39
• 6.6.40
• 6.6.41
• 6.6.42
• 6.6.43
• 6.6.44
• 6.10.0
• 6.10.1
• 6.10.2
• 6.10.3

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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Sourcesinfo

Entryinfo

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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