CVE-2023-53999 net/mlx5e: TC, Fix internal port memory leak
A memory leak in the Linux kernel mlx5e driver allows local attackers with high privileges to cause denial of service by exhausting kernel memory.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2023-53999?
CVE-2023-53999 is a memory corruption vulnerability in Linux, published on 24 Dec 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
net/mlx5e: TC, Fix internal port memory leak
The flow rule can be splited, and the extra post_act rules are added to post_act table. It's possible to trigger memleak when the rule forwards packets from internal port and over tunnel, in the case that, for example, CT 'new' state offload is allowed. As int_port object is assigned to the flow attribute of post_act rule, and its refcnt is incremented by mlx5e_tc_int_port_get(), but mlx5e_tc_int_port_put() is not called, the refcnt is never decremented, then int_port is never freed.
The kmemleak reports the following error: unreferenced object 0xffff888128204b80 (size 64): comm "handler20", pid 50121, jiffies 4296973009 (age 642.932s) hex dump (first 32 bytes): 01 00 00 00 19 00 00 00 03 f0 00 00 04 00 00 00 ................ 98 77 67 41 81 88 ff ff 98 77 67 41 81 88 ff ff .wgA.....wgA.... backtrace: [<00000000e992680d>] kmalloc_trace+0x27/0x120 [<000000009e945a98>] mlx5e_tc_int_port_get+0x3f3/0xe20 [mlx5_core] [<0000000035a537f0>] mlx5e_tc_add_fdb_flow+0x473/0xcf0 [mlx5_core] [<0000000070c2cec6>] __mlx5e_add_fdb_flow+0x7cf/0xe90 [mlx5_core] [<000000005cc84048>] mlx5e_configure_flower+0xd40/0x4c40 [mlx5_core] [<000000004f8a2031>] mlx5e_rep_indr_offload.isra.0+0x10e/0x1c0 [mlx5_core] [<000000007df797dc>] mlx5e_rep_indr_setup_tc_cb+0x90/0x130 [mlx5_core] [<0000000016c15cc3>] tc_setup_cb_add+0x1cf/0x410 [<00000000a63305b4>] fl_hw_replace_filter+0x38f/0x670 [cls_flower] [<000000008bc9e77c>] fl_change+0x1fd5/0x4430 [cls_flower] [<00000000e7f766e4>] tc_new_tfilter+0x867/0x2010 [<00000000e101c0ef>] rtnetlink_rcv_msg+0x6fc/0x9f0 [<00000000e1111d44>] netlink_rcv_skb+0x12c/0x360 [<0000000082dd6c8b>] netlink_unicast+0x438/0x710 [<00000000fc568f70>] netlink_sendmsg+0x794/0xc50 [<0000000016e92590>] sock_sendmsg+0xc5/0x190
So fix this by moving int_port cleanup code to the flow attribute free helper, which is used by all the attribute free cases.
Which versions are affected by CVE-2023-53999?
How do I fix CVE-2023-53999?
Apply the vendor's patch.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2023-53999 being exploited?
There is no known exploitation of CVE-2023-53999 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2023-53999, DEBIAN-CVE-2023-53999, GHSA-x7x5-xvrp-r655, ROOT-OS-DEBIAN-12-CVE-2023-53999, UBUNTU-CVE-2023-53999.