SEPTEMBER 8, 2026
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Case File

CVE-2026-63995

HIGH · CVSS 7.8 EPSS 0.13%

Source: NVD + CISA KEV + EPSS · Published 2026-07-19 · Last synced 2026-08-18

CyberRota Analysis

AI-Generated

The vulnerability affects the Linux kernel's ethtool component, specifically in the CMIS firmware update process, where an improperly validated payload size can lead to an out-of-bounds write. This flaw poses a high risk as it could allow a malicious module or a corrupted response to overwrite memory, potentially leading to system crashes or arbitrary code execution. Organizations using Linux systems, particularly those relying on CMIS firmware updates, should prioritize patching this vulnerability to mitigate the associated risks.

CVE
CVE-2026-63995
Severity
HIGH
CVSS
7.8
EPSS
0.13%
Linux

Original NVD Description

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.