GHSA-6G47-HQW2-HV2R
Vulnerability from github – Published: 2026-08-21 18:34 – Updated: 2026-08-27 15:31In the Linux kernel, the following vulnerability has been resolved:
packet: use consistent hard_header_len in non-ring send paths
packet_snd() reads dev->hard_header_len multiple times while allocating and constructing an skb. Device reconfiguration can change this value concurrently, for example through bonding device type changes.
For SOCK_RAW, packet_snd() can save a larger value in reserve and later allocate headroom using a smaller value. Moving skb->data back by reserve then places it before skb->head, and the following copy from userspace can attempt an out-of-bounds write.
packet_sendmsg_spkt() has the same issue because it calculates its reservation and header offset from separate reads before dropping the RCU read lock to allocate the skb.
Add LL_RESERVED_SPACE_EX() for callers that already saved a header length. Read hard_header_len once in packet_snd() and use it for allocation and construction. In packet_sendmsg_spkt(), preserve the allocation-time value through the device lookup retry.
The separate SOCK_DGRAM consistency problem between hard_header_len and header_ops->create is not addressed here.
{
"affected": [],
"aliases": [
"CVE-2026-74582"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-08-21T17:16:44Z",
"severity": "HIGH"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\npacket: use consistent hard_header_len in non-ring send paths\n\npacket_snd() reads dev-\u003ehard_header_len multiple times while allocating\nand constructing an skb. Device reconfiguration can change this value\nconcurrently, for example through bonding device type changes.\n\nFor SOCK_RAW, packet_snd() can save a larger value in reserve and later\nallocate headroom using a smaller value. Moving skb-\u003edata back by reserve\nthen places it before skb-\u003ehead, and the following copy from userspace can\nattempt an out-of-bounds write.\n\npacket_sendmsg_spkt() has the same issue because it calculates its\nreservation and header offset from separate reads before dropping the RCU\nread lock to allocate the skb.\n\nAdd LL_RESERVED_SPACE_EX() for callers that already saved a header length.\nRead hard_header_len once in packet_snd() and use it for allocation and\nconstruction. In packet_sendmsg_spkt(), preserve the allocation-time value\nthrough the device lookup retry.\n\nThe separate SOCK_DGRAM consistency problem between hard_header_len and\nheader_ops-\u003ecreate is not addressed here.",
"id": "GHSA-6g47-hqw2-hv2r",
"modified": "2026-08-27T15:31:29Z",
"published": "2026-08-21T18:34:58Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-74582"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/03390aa32e669cc4ecd7d34108e2e1afc13d689d"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/142e287b3a25cfe909215177c23243e7fc5ae2b1"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/5bb10753d428aadfc356a2bfe9acea09c82a62ec"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/78a47127e33c340bc6d38dcc4552a094b4f5cc77"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/9052756290962ffb9a661bcf319e92dedaaedfed"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/91f041451f967cd87ed722a8f43c0b767a64f1a0"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/b06b6fce6d7deaf7238e09b48ce3b1125ff41acd"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/bcd4df60ac9481b1ceffdfe5ec38fe51dcaae812"
}
],
"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"
}
]
}
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
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The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.