linux-cve-announce - CVE-2025-39979: net/mlx5: fs, fix UAF in flow counter release

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Message-ID: <2025101559-CVE-2025-39979-f1e9@gregkh>
Date: Wed, 15 Oct 2025 09:57:07 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2025-39979: net/mlx5: fs, fix UAF in flow counter release

From: Greg Kroah-Hartman <gregkh@...nel.org>

Description
===========

In the Linux kernel, the following vulnerability has been resolved:

net/mlx5: fs, fix UAF in flow counter release

Fix a kernel trace [1] caused by releasing an HWS action of a local flow
counter in mlx5_cmd_hws_delete_fte(), where the HWS action refcount and
mutex were not initialized and the counter struct could already be freed
when deleting the rule.

Fix it by adding the missing initializations and adding refcount for the
local flow counter struct.

[1] Kernel log:
 Call Trace:
  <TASK>
  dump_stack_lvl+0x34/0x48
  mlx5_fs_put_hws_action.part.0.cold+0x21/0x94 [mlx5_core]
  mlx5_fc_put_hws_action+0x96/0xad [mlx5_core]
  mlx5_fs_destroy_fs_actions+0x8b/0x152 [mlx5_core]
  mlx5_cmd_hws_delete_fte+0x5a/0xa0 [mlx5_core]
  del_hw_fte+0x1ce/0x260 [mlx5_core]
  mlx5_del_flow_rules+0x12d/0x240 [mlx5_core]
  ? ttwu_queue_wakelist+0xf4/0x110
  mlx5_ib_destroy_flow+0x103/0x1b0 [mlx5_ib]
  uverbs_free_flow+0x20/0x50 [ib_uverbs]
  destroy_hw_idr_uobject+0x1b/0x50 [ib_uverbs]
  uverbs_destroy_uobject+0x34/0x1a0 [ib_uverbs]
  uobj_destroy+0x3c/0x80 [ib_uverbs]
  ib_uverbs_run_method+0x23e/0x360 [ib_uverbs]
  ? uverbs_finalize_object+0x60/0x60 [ib_uverbs]
  ib_uverbs_cmd_verbs+0x14f/0x2c0 [ib_uverbs]
  ? do_tty_write+0x1a9/0x270
  ? file_tty_write.constprop.0+0x98/0xc0
  ? new_sync_write+0xfc/0x190
  ib_uverbs_ioctl+0xd7/0x160 [ib_uverbs]
  __x64_sys_ioctl+0x87/0xc0
  do_syscall_64+0x59/0x90

The Linux kernel CVE team has assigned CVE-2025-39979 to this issue.

Affected and fixed versions
===========================

	Issue introduced in 6.14 with commit b581f4266928d3b5d1bbe711e39623d9a1696091 and fixed in 6.16.10 with commit 3c77f6d244188c3fb11f6aec40bbfe884f1803b5
	Issue introduced in 6.14 with commit b581f4266928d3b5d1bbe711e39623d9a1696091 and fixed in 6.17 with commit 6043819e707cefb1c9e59d6e431dcfa735c4f975

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2025-39979
will be updated if fixes are backported, please check that for the most
up to date information about this issue.

Affected files
==============

The file(s) affected by this issue are:
	drivers/net/ethernet/mellanox/mlx5/core/fs_core.c
	drivers/net/ethernet/mellanox/mlx5/core/fs_core.h
	drivers/net/ethernet/mellanox/mlx5/core/fs_counters.c
	drivers/net/ethernet/mellanox/mlx5/core/steering/hws/fs_hws_pools.c
	include/linux/mlx5/fs.h

Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/3c77f6d244188c3fb11f6aec40bbfe884f1803b5
	https://git.kernel.org/stable/c/6043819e707cefb1c9e59d6e431dcfa735c4f975