CVE-2026-63995

ethtool: cmis: validate start_cmd_payload_size from module

HIGH
7.8
CVSS Score
Published: July 19, 2026 at 02:56 PM UTC
Updated: October 19, 2026 at 09:17 PM UTC
1 product affected across 1 vendorLinux Kernel

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Severity
HIGH7.8
Exploit prediction
EPSS 0.1%
SSVC
No known exploit

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

6.11 ≤ v < 6.12.936.13 ≤ v < 6.18.356.19 ≤ v < 7.0.127.17.1 rc17.1 rc27.1 rc37.1 rc47.1 rc5c4f78134d45c9619339c96b4bea380b1d0699788
Vendor states this is fixed in 0696709e951be54c699664adf546d16e28974d53 (fixed)
Vendor states this is fixed in 12c2496a71f82f63617971ca9b730dffa05cf58b (fixed)
Vendor states this is fixed in 63112b4515469d00008452d9cfe3fb3bf1aa2df3 (fixed)
Vendor states this is fixed in a46340da00385be7fb16c62425ebc20006f2d5d8 (fixed)
Vendor states this is fixed in 6.11 (unaffected)
Vendor states this is fixed in 6.12.93 (unaffected)
Vendor states this is fixed in 6.18.35 (unaffected)
Vendor states this is fixed in 7.0.12 (unaffected)
Vendor states this is fixed in 7.1 (unaffected)

SSVC — Action Prioritization

SSVCNo known exploitNot automatableTotal impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

7.8HIGHLinux
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-787

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