Linux Kernel up to 6.19-rc1 mlxsw spectrum_mr use after free

Summaryinfo

A vulnerability marked as critical has been reported in Linux Kernel up to 6.1.159/6.6.119/6.12.63/6.18.2/6.19-rc1. This affects the function spectrum_mr of the component mlxsw. Performing a manipulation results in use after free. This vulnerability is reported as CVE-2025-68800. No exploit exists. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as critical, was found in Linux Kernel up to 6.1.159/6.6.119/6.12.63/6.18.2/6.19-rc1. This affects the function spectrum_mr of the component mlxsw. The manipulation with an unknown input leads to a use after free vulnerability. CWE is classifying the issue as CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: mlxsw: spectrum_mr: Fix use-after-free when updating multicast route stats Cited commit added a dedicated mutex (instead of RTNL) to protect the multicast route list, so that it will not change while the driver periodically traverses it in order to update the kernel about multicast route stats that were queried from the device. One instance of list entry deletion (during route replace) was missed and it can result in a use-after-free [1]. Fix by acquiring the mutex before deleting the entry from the list and releasing it afterwards. [1] BUG: KASAN: slab-use-after-free in mlxsw_sp_mr_stats_update+0x4a5/0x540 drivers/net/ethernet/mellanox/mlxsw/spectrum_mr.c:1006 [mlxsw_spectrum] Read of size 8 at addr ffff8881523c2fa8 by task kworker/2:5/22043 CPU: 2 UID: 0 PID: 22043 Comm: kworker/2:5 Not tainted 6.18.0-rc1-custom-g1a3d6d7cd014 #1 PREEMPT(full) Hardware name: Mellanox Technologies Ltd. MSN2010/SA002610, BIOS 5.6.5 08/24/2017 Workqueue: mlxsw_core mlxsw_sp_mr_stats_update [mlxsw_spectrum] Call Trace: <TASK> dump_stack_lvl+0xba/0x110 print_report+0x174/0x4f5 kasan_report+0xdf/0x110 mlxsw_sp_mr_stats_update+0x4a5/0x540 drivers/net/ethernet/mellanox/mlxsw/spectrum_mr.c:1006 [mlxsw_spectrum] process_one_work+0x9cc/0x18e0 worker_thread+0x5df/0xe40 kthread+0x3b8/0x730 ret_from_fork+0x3e9/0x560 ret_from_fork_asm+0x1a/0x30 </TASK> Allocated by task 29933: kasan_save_stack+0x30/0x50 kasan_save_track+0x14/0x30 __kasan_kmalloc+0x8f/0xa0 mlxsw_sp_mr_route_add+0xd8/0x4770 [mlxsw_spectrum] mlxsw_sp_router_fibmr_event_work+0x371/0xad0 drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c:7965 [mlxsw_spectrum] process_one_work+0x9cc/0x18e0 worker_thread+0x5df/0xe40 kthread+0x3b8/0x730 ret_from_fork+0x3e9/0x560 ret_from_fork_asm+0x1a/0x30 Freed by task 29933: kasan_save_stack+0x30/0x50 kasan_save_track+0x14/0x30 __kasan_save_free_info+0x3b/0x70 __kasan_slab_free+0x43/0x70 kfree+0x14e/0x700 mlxsw_sp_mr_route_add+0x2dea/0x4770 drivers/net/ethernet/mellanox/mlxsw/spectrum_mr.c:444 [mlxsw_spectrum] mlxsw_sp_router_fibmr_event_work+0x371/0xad0 drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c:7965 [mlxsw_spectrum] process_one_work+0x9cc/0x18e0 worker_thread+0x5df/0xe40 kthread+0x3b8/0x730 ret_from_fork+0x3e9/0x560 ret_from_fork_asm+0x1a/0x30

The advisory is shared at git.kernel.org. This vulnerability is uniquely identified as CVE-2025-68800 since 12/24/2025. The exploitability is told 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 03/27/2026).

The vulnerability scanner Nessus provides a plugin with the ID 283664 (Linux Distros Unpatched Vulnerability : CVE-2025-68800), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 6.1.160, 6.6.120, 6.12.64, 6.18.3 or 6.19-rc2 eliminates this vulnerability. Applying the patch 37ca08b35a27ce8fd8e74dd3fd2ae21c23b63b73/5f2831fc593c2b2efbff7dd0dd7441cec76adcd5/216afc198484fde110ebeafc017992266f4596ce/4049a6ace209f4ed150429f86ae796d7d6a4c22b/8ac1dacec458f55f871f7153242ed6ab60373b90 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 (283664) and CERT Bund (WID-SEC-2026-0086). 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
• Oracle Linux
• SUSE openSUSE
• RESF Rocky Linux
• Open Source Linux Kernel

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 6.1.159
• 6.6.119
• 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
• 6.12.13
• 6.12.14
• 6.12.15
• 6.12.16
• 6.12.17
• 6.12.18
• 6.12.19
• 6.12.20
• 6.12.21
• 6.12.22
• 6.12.23
• 6.12.24
• 6.12.25
• 6.12.26
• 6.12.27
• 6.12.28
• 6.12.29
• 6.12.30
• 6.12.31
• 6.12.32
• 6.12.33
• 6.12.34
• 6.12.35
• 6.12.36
• 6.12.37
• 6.12.38
• 6.12.39
• 6.12.40
• 6.12.41
• 6.12.42
• 6.12.43
• 6.12.44
• 6.12.45
• 6.12.46
• 6.12.47
• 6.12.48
• 6.12.49
• 6.12.50
• 6.12.51
• 6.12.52
• 6.12.53
• 6.12.54
• 6.12.55
• 6.12.56
• 6.12.57
• 6.12.58
• 6.12.59
• 6.12.60
• 6.12.61
• 6.12.62
• 6.12.63
• 6.18.0
• 6.18.1
• 6.18.2
• 6.19-rc1

License

• open-source

Website

• Vendor: https://www.kernel.org/

CPE 2.3info

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CPE 2.2info

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Entryinfo

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

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