ethtool: cmis: require exact CDB reply length
In the Linux kernel, the following vulnerability has been resolved: ethtool: cmis: require exact CDB reply length Malicious SFP module could respond with rpl_len longer than what cmis_cdb_process_reply() expected, leading to OOB writes. Malicious HW is a bit theoretical but some modules may just be buggy and/or the reads may occasionally get corrupted, so let's protect the kernel. The existing check protects from short replies. We need to protect from long ones, too. All callers that pass a non-zero rpl_exp_len cast the reply payload to a fixed-layout struct and read fields at fixed offsets, with no version negotiation or short-reply handling: - cmis_cdb_validate_password() - cmis_cdb_module_features_get() - cmis_fw_update_fw_mng_features_get() so let's assume that responses longer than expected do not have to be handled gracefully here. Add a warning message to make the debug easier in case my understanding is wrong... Note that page_data->length (argument of kmalloc) comes from last arg to ethtool_cmis_page_init() which is rpl_exp_len. Note2 that AIs also like to point out overflows in args->req.payload itself (which is a fixed-size 120 B buffer, on the stack), but callers should be reading structs defined by the standard, so protecting from requests for more data than max seem like defensive programming.
CVE-2026-63996
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2026-63996
Linux
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Linux
Source reference: /containers/cna/affected/1/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "a39c84d796254e6b1662ca0c46dbc313379e9291",
"lessThan": "2f818cc98fd2c63a08239cb48995f6c3bfe9d9b3",
"versionType": "git"
},
{
"status": "affected",
"version": "a39c84d796254e6b1662ca0c46dbc313379e9291",
"lessThan": "4d42fb88ec61f2e98c33a9e3a2de371d5edbc6b1",
"versionType": "git"
},
{
"status": "affected",
"version": "a39c84d796254e6b1662ca0c46dbc313379e9291",
"lessThan": "eb5dcd740cd7fa27bc2caeff2d28ef28e93ff4d3",
"versionType": "git"
},
{
"status": "affected",
"version": "a39c84d796254e6b1662ca0c46dbc313379e9291",
"lessThan": "6c3f999a9d1338c6c89a9ff4549eafe72bc2e7b1",
"versionType": "git"
}
],
"programFiles": [
"net/ethtool/cmis_cdb.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "6.11"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "6.11",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "6.12.93",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.35",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.0.12",
"versionType": "semver",
"lessThanOrEqual": "7.0.*"
},
{
"status": "unaffected",
"version": "7.1",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"net/ethtool/cmis_cdb.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-63996
Source reference:
/cveMetadata/cveId
Publisher severity
high
Source reference: /containers/cna/metrics
- Event
- #40925 · Revision 1
- Added to Heist Feed
- Publisher date