Linux Kernel up to 6.12.12/6.13.1 ravb rcu_dereference_protected null pointer dereference

Summaryinfo

A vulnerability, which was classified as critical, was found in Linux Kernel up to 6.12.12/6.13.1. Affected by this vulnerability is the function rcu_dereference_protected of the component ravb. Executing a manipulation can lead to null pointer dereference. This vulnerability is registered as CVE-2025-21801. No exploit is available. You should upgrade the affected component.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.12.12/6.13.1. It has been declared as critical. This vulnerability affects the function rcu_dereference_protected of the component ravb. The manipulation with an unknown input leads to a null pointer dereference vulnerability. The CWE definition for the vulnerability is CWE-476. A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit. As an impact it is known to affect availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: net: ravb: Fix missing rtnl lock in suspend/resume path Fix the suspend/resume path by ensuring the rtnl lock is held where required. Calls to ravb_open, ravb_close and wol operations must be performed under the rtnl lock to prevent conflicts with ongoing ndo operations. Without this fix, the following warning is triggered: [ 39.032969] ============================= [ 39.032983] WARNING: suspicious RCU usage [ 39.033019] ----------------------------- [ 39.033033] drivers/net/phy/phy_device.c:2004 suspicious rcu_dereference_protected() usage! ... [ 39.033597] stack backtrace: [ 39.033613] CPU: 0 UID: 0 PID: 174 Comm: python3 Not tainted 6.13.0-rc7-next-20250116-arm64-renesas-00002-g35245dfdc62c #7 [ 39.033623] Hardware name: Renesas SMARC EVK version 2 based on r9a08g045s33 (DT) [ 39.033628] Call trace: [ 39.033633] show_stack+0x14/0x1c (C) [ 39.033652] dump_stack_lvl+0xb4/0xc4 [ 39.033664] dump_stack+0x14/0x1c [ 39.033671] lockdep_rcu_suspicious+0x16c/0x22c [ 39.033682] phy_detach+0x160/0x190 [ 39.033694] phy_disconnect+0x40/0x54 [ 39.033703] ravb_close+0x6c/0x1cc [ 39.033714] ravb_suspend+0x48/0x120 [ 39.033721] dpm_run_callback+0x4c/0x14c [ 39.033731] device_suspend+0x11c/0x4dc [ 39.033740] dpm_suspend+0xdc/0x214 [ 39.033748] dpm_suspend_start+0x48/0x60 [ 39.033758] suspend_devices_and_enter+0x124/0x574 [ 39.033769] pm_suspend+0x1ac/0x274 [ 39.033778] state_store+0x88/0x124 [ 39.033788] kobj_attr_store+0x14/0x24 [ 39.033798] sysfs_kf_write+0x48/0x6c [ 39.033808] kernfs_fop_write_iter+0x118/0x1a8 [ 39.033817] vfs_write+0x27c/0x378 [ 39.033825] ksys_write+0x64/0xf4 [ 39.033833] __arm64_sys_write+0x18/0x20 [ 39.033841] invoke_syscall+0x44/0x104 [ 39.033852] el0_svc_common.constprop.0+0xb4/0xd4 [ 39.033862] do_el0_svc+0x18/0x20 [ 39.033870] el0_svc+0x3c/0xf0 [ 39.033880] el0t_64_sync_handler+0xc0/0xc4 [ 39.033888] el0t_64_sync+0x154/0x158 [ 39.041274] ravb 11c30000.ethernet eth0: Link is Down

The advisory is shared for download at git.kernel.org. This vulnerability was named CVE-2025-21801 since 12/29/2024. The exploitation appears to be difficult. There are known technical details, but no exploit is available.

The vulnerability scanner Nessus provides a plugin with the ID 230739 (Linux Distros Unpatched Vulnerability : CVE-2025-21801), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 6.12.13, 6.13.2 or 6.14-rc1 eliminates this vulnerability. Applying the patch ad19522c007bb24ed874468f8baa1503c4662cf4/2c2ebb2b49573e5f8726112ad06b1dffc3c9ea03 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 (230739) and CERT Bund (WID-SEC-2025-0461). VulDB is the best source for vulnerability data and more expert information about this specific topic.

Affected

• Google Container-Optimized OS
• Debian Linux
• Amazon Linux 2
• Red Hat Enterprise Linux
• Ubuntu Linux
• SUSE Linux
• Oracle Linux
• SUSE openSUSE
• Open Source Linux Kernel
• Dell Secure Connect Gateway

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 6.12.0
• 6.12.1
• 6.12.2
• 6.12.3
• 6.12.4
• 6.12.5
• 6.12.6
• 6.12.7
• 6.12.8
• 6.12.9
• 6.12.10
• 6.12.11
• 6.12.12
• 6.13.0
• 6.13.1

License

• open-source

Website

• Vendor: https://www.kernel.org/

CPE 2.3info

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CPE 2.2info

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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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