Vulnerability in Linux

CVE-2026-63995

In the Linux kernel, the following vulnerability has been resolved: ethtool: cmis: validate start_cmd_payload_size from module The CMIS firmware update code reads start_cmd_payload_size from the module's FW Management Features CDB reply and uses it directly as the byte count for memcpy. The destination buffer is 112 bytes (ETHTOOL_CMIS_CDB_LPL_MAX_PL_LENGTH - 8). So a malicious module (or corrupted response) can cause a OOB write later on in cmis_fw_update_start_download(). Let's error out. If modules that expect longer LPL writes actually exist we should revisit. struct cmis_cdb_start_fw_download_pl's definition has to move, no change there.

EPSS: 0.001 (2.8th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 7.8 (High). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

Affected products

  • Linux — versions c4f78134d45c9619339c96b4bea380b1d0699788, 6.11, 0

References

Frequently asked questions

What is CVE-2026-63995?
CVE-2026-63995 is a high-severity vulnerability in Linux. CVSS score: 7.8/10. Published 2026-07-19.
How severe is CVE-2026-63995?
High severity. CVSS v3 base score is 7.8 out of 10.