GHSA-G8C6-C8PH-PP93
Vulnerability from github – Published: 2026-07-19 18:31 – Updated: 2026-07-20 15:31In 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.
{
"affected": [],
"aliases": [
"CVE-2026-63995"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-07-19T16:17:39Z",
"severity": "HIGH"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nethtool: cmis: validate start_cmd_payload_size from module\n\nThe CMIS firmware update code reads start_cmd_payload_size from\nthe module\u0027s FW Management Features CDB reply and uses it directly\nas the byte count for memcpy. The destination buffer is 112 bytes\n(ETHTOOL_CMIS_CDB_LPL_MAX_PL_LENGTH - 8). So a malicious\nmodule (or corrupted response) can cause a OOB write later on in\ncmis_fw_update_start_download().\n\nLet\u0027s error out. If modules that expect longer LPL writes actually\nexist we should revisit.\n\nstruct cmis_cdb_start_fw_download_pl\u0027s definition has to move,\nno change there.",
"id": "GHSA-g8c6-c8ph-pp93",
"modified": "2026-07-20T15:31:54Z",
"published": "2026-07-19T18:31:48Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-63995"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/0696709e951be54c699664adf546d16e28974d53"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/12c2496a71f82f63617971ca9b730dffa05cf58b"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/63112b4515469d00008452d9cfe3fb3bf1aa2df3"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/a46340da00385be7fb16c62425ebc20006f2d5d8"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
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