CVE-2021-47556

Advisory lineage Upstream: 0 Downstream: 11
Modified
Published: 24 May 2024, 15:09
Last modified:11 May 2026, 13:56

Vulnerability Summary

Overall Risk (default)
low
22/100
CVSS Score
5.5 MEDIUM
v3.1 (nvd)
EPSS Score
0.03% LOW
0% probability +0.01%
KEV
Not listed
Ransomware
No reports
Public exploits
None found
Dark Web
Not detected

Timeline

24 May 2024, 15:09
Published
Vulnerability first disclosed
11 May 2026, 13:56
Last Modified
Vulnerability information updated

Description

In the Linux kernel, the following vulnerability has been resolved: ethtool: ioctl: fix potential NULL deref in ethtool_set_coalesce() ethtool_set_coalesce() now uses both the .get_coalesce() and .set_coalesce() callbacks. But the check for their availability is buggy, so changing the coalesce settings on a device where the driver provides only _one_ of the callbacks results in a NULL pointer dereference instead of an -EOPNOTSUPP. Fix the condition so that the availability of both callbacks is ensured. This also matches the netlink code. Note that reproducing this requires some effort - it only affects the legacy ioctl path, and needs a specific combination of driver options: - have .get_coalesce() and .coalesce_supported but no .set_coalesce(), or - have .set_coalesce() but no .get_coalesce(). Here eg. ethtool doesn't cause the crash as it first attempts to call ethtool_get_coalesce() and bails out on error.

CVSS Metrics

  • v3.1•MEDIUM•Score: 5.5CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

EPSS Trends

Current EPSS score: 0.03%• Percentile: 9%

Techniques & Countermeasures

  • CWE-476•NULL Pointer Dereference

    The product dereferences a pointer that it expects to be valid but is NULL.

Affected Systems

  • linux•linux

    ≥ f3ccfda1931977b80267ba54070a1aeafa18f6ca, < abfdd9e2f0f9699015d72317f74154d3e53664e6 | ≥ f3ccfda1931977b80267ba54070a1aeafa18f6ca, < 0276af2176c78771da7f311621a25d7608045827 | 5.15

  • linux•linux_kernel

    ≥ 5.15, < 5.15.6

References (2)