SB20260720231 - Out-of-bounds write in Linux kernel ethtool

Description

This security bulletin contains information about 1 vulnerability.

1) Out-of-bounds write (CVE-ID: CVE-2026-63996)

CWE-ID: CWE-787 - Out-of-bounds write

CVSSv4: 5.1 [CVSS:4.0/AV:P/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

The vulnerability allows an attacker with physical access to cause a denial of service.

The vulnerability exists due to out-of-bounds write in cmis_cdb_process_reply() when processing a crafted CDB reply from an SFP module. An attacker with physical access can provide a malicious SFP module that returns an overlong reply to cause a denial of service.

The issue can be triggered by a malicious module, and the advisory notes that buggy hardware or corrupted reads may also reach the vulnerable condition.

Remediation

Install update from vendor's website.

References

• https://git.kernel.org/stable/c/2f818cc98fd2c63a08239cb48995f6c3bfe9d9b3
• https://git.kernel.org/stable/c/4d42fb88ec61f2e98c33a9e3a2de371d5edbc6b1
• https://git.kernel.org/stable/c/6c3f999a9d1338c6c89a9ff4549eafe72bc2e7b1
• https://git.kernel.org/stable/c/eb5dcd740cd7fa27bc2caeff2d28ef28e93ff4d3