usb: gadget: f_ncm: validate minimum block_len in ncm_unwrap_ntb()
In the Linux kernel, the following vulnerability has been resolved: usb: gadget: f_ncm: validate minimum block_len in ncm_unwrap_ntb() The block_len read from the host-supplied NTB header is checked against ntb_max but has no lower bound. When block_len is smaller than opts->ndp_size, the bounds check of: ndp_index > (block_len - opts->ndp_size) will underflow producing a huge unsigned value that ndp_index can never exceed, defeating the check entirely. The same underflow occurs in the datagram index checks against block_len - opts->dpe_size. With those checks neutered, a malicious USB host can choose ndp_index and datagram offsets that point past the actual transfer, and the skb_put_data() copies adjacent kernel memory into the network skb. Fix this by rejecting block lengths that cannot hold at least the NTB header plus one NDP. This will make block_len - opts->ndp_size and block_len - opts->dpe_size both well-defined. Commit 8d2b1a1ec9f5 ("CDC-NCM: avoid overflow in sanity checking") fixed a related class of issues on the host side of NCM.
CVE-2026-31617
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-2026-31617
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": "2b74b0a04d3e9f9f08ff026e5663dce88ff94e52",
"lessThan": "068a7f2749fff6462a0a908ec415b885fe430f50",
"versionType": "git"
},
{
"status": "affected",
"version": "2b74b0a04d3e9f9f08ff026e5663dce88ff94e52",
"lessThan": "1425655c2870054c3ab4712e2b6dbdd331597ada",
"versionType": "git"
},
{
"status": "affected",
"version": "2b74b0a04d3e9f9f08ff026e5663dce88ff94e52",
"lessThan": "8b3b7bd3c02f98634baaf36c7fc7ac915f6517ca",
"versionType": "git"
},
{
"status": "affected",
"version": "2b74b0a04d3e9f9f08ff026e5663dce88ff94e52",
"lessThan": "0f156bb5334e588034ca68ac2ee92b23f66e56e7",
"versionType": "git"
},
{
"status": "affected",
"version": "2b74b0a04d3e9f9f08ff026e5663dce88ff94e52",
"lessThan": "8757a2593631443648218244b9788e193ae0fdc1",
"versionType": "git"
},
{
"status": "affected",
"version": "2b74b0a04d3e9f9f08ff026e5663dce88ff94e52",
"lessThan": "6762f8a95772265dd0c2ffe7f400493f3115b135",
"versionType": "git"
},
{
"status": "affected",
"version": "2b74b0a04d3e9f9f08ff026e5663dce88ff94e52",
"lessThan": "d58ba8f6546232f8414f396c189297dbee03f1a7",
"versionType": "git"
},
{
"status": "affected",
"version": "2b74b0a04d3e9f9f08ff026e5663dce88ff94e52",
"lessThan": "74908b0318d1df1188457040b8714ff4d4b68126",
"versionType": "git"
},
{
"status": "affected",
"version": "2b74b0a04d3e9f9f08ff026e5663dce88ff94e52",
"lessThan": "8f993d30b95dc9557a8a96ceca11abed674c8acb",
"versionType": "git"
},
{
"status": "affected",
"version": "f7e0611e207d8908c4f2858e244370529a76dbf7",
"versionType": "git"
},
{
"status": "affected",
"version": "b88ad6e714284b33a47834f5f2a294c2b37c66aa",
"versionType": "git"
},
{
"status": "affected",
"version": "471b23586387a32857778c511be60ab31c98dcfd",
"versionType": "git"
},
{
"status": "affected",
"version": "4f529c4d1e436230d3af7c09a3239677a14d2b46",
"versionType": "git"
},
{
"status": "affected",
"version": "ae6a5394d9fbe118bc95cfe376d6a9d91d7547e8",
"versionType": "git"
},
{
"status": "affected",
"version": "4.9.235",
"lessThan": "4.10",
"versionType": "semver"
},
{
"status": "affected",
"version": "4.14.196",
"lessThan": "4.15",
"versionType": "semver"
},
{
"status": "affected",
"version": "4.19.143",
"lessThan": "4.20",
"versionType": "semver"
},
{
"status": "affected",
"version": "5.4.62",
"lessThan": "5.5",
"versionType": "semver"
},
{
"status": "affected",
"version": "5.8.6",
"lessThan": "5.9",
"versionType": "semver"
}
],
"programFiles": [
"drivers/usb/gadget/function/f_ncm.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "5.9"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "5.9",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "5.10.258",
"versionType": "semver",
"lessThanOrEqual": "5.10.*"
},
{
"status": "unaffected",
"version": "5.15.209",
"versionType": "semver",
"lessThanOrEqual": "5.15.*"
},
{
"status": "unaffected",
"version": "6.1.175",
"versionType": "semver",
"lessThanOrEqual": "6.1.*"
},
{
"status": "unaffected",
"version": "6.6.136",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.83",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.24",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "6.19.14",
"versionType": "semver",
"lessThanOrEqual": "6.19.*"
},
{
"status": "unaffected",
"version": "7.0.1",
"versionType": "semver",
"lessThanOrEqual": "7.0.*"
},
{
"status": "unaffected",
"version": "7.1",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"drivers/usb/gadget/function/f_ncm.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-31617
Source reference:
/cveMetadata/cveId
Publisher severity
No explicit severity was provided.
- Event
- #28299 · Revision 1
- Added to Heist Feed
- Publisher date