net/packet: reset the MAC header on the packet-socket transmit path
In the Linux kernel, the following vulnerability has been resolved: net/packet: reset the MAC header on the packet-socket transmit path packet_parse_headers() resets the MAC header only for a SOCK_RAW frame whose socket did not bind a protocol. A protocol-bound SOCK_RAW socket, any SOCK_DGRAM frame, and the legacy SOCK_PACKET path therefore leave skb->mac_header unset here. For frames sent via __dev_queue_xmit() this is harmless: it resets the MAC header unconditionally. But the packet-socket PACKET_QDISC_BYPASS path uses dev_direct_xmit(), which does not, so the frame reaches ndo_start_xmit() with the MAC header unset. A driver that reads eth_hdr(skb) on transmit then dereferences skb->head + (u16)~0, an out-of-bounds access ~64 KiB past the head -- the same class fixed for one consumer in commit f5089008f90c ("macsec: do not read an unset MAC header in macsec_encrypt()"). packet_parse_headers() runs only on the transmit path, where skb->data points at the start of the L2 header for every packet-socket type regardless of its length: SOCK_RAW and SOCK_PACKET carry a user-supplied header and SOCK_DGRAM has one built by dev_hard_header(). Reset the MAC header unconditionally, mirroring __dev_queue_xmit(), so the frame is anchored on the bypass path too. Found by 0sec (https://0sec.ai) using automated source analysis; verified against source and matched to the macsec KASAN report in f5089008f90c. Compile-tested.
CVE-2026-74667
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-2026-74667
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": "75c65772c3d18447d62d3aca5f91b06c16cc25e4",
"lessThan": "1e43a1d66615f411d427f9df1f46dd049d9e3681",
"versionType": "git"
},
{
"status": "affected",
"version": "75c65772c3d18447d62d3aca5f91b06c16cc25e4",
"lessThan": "4057853a91fb796c4f47c7d1baf1aa085394148e",
"versionType": "git"
},
{
"status": "affected",
"version": "75c65772c3d18447d62d3aca5f91b06c16cc25e4",
"lessThan": "2610ed4e86a4590234a9d70518c469751c5af231",
"versionType": "git"
},
{
"status": "affected",
"version": "75c65772c3d18447d62d3aca5f91b06c16cc25e4",
"lessThan": "b47ba8fe6e1d2df8c92048de5afafd059447dc30",
"versionType": "git"
},
{
"status": "affected",
"version": "75c65772c3d18447d62d3aca5f91b06c16cc25e4",
"lessThan": "284f3e7a3f1a743fdf89e304fd1f19d5ffcff46d",
"versionType": "git"
},
{
"status": "affected",
"version": "75c65772c3d18447d62d3aca5f91b06c16cc25e4",
"lessThan": "971aa7d99242bbf09513e27b7a243f0b29ff23ae",
"versionType": "git"
},
{
"status": "affected",
"version": "75c65772c3d18447d62d3aca5f91b06c16cc25e4",
"lessThan": "fdd4d7d52358a58e351dd9d82530c04eba8ccd7a",
"versionType": "git"
},
{
"status": "affected",
"version": "75c65772c3d18447d62d3aca5f91b06c16cc25e4",
"lessThan": "c2707480cfbf19c7619acc9c089d17f20869821f",
"versionType": "git"
}
],
"programFiles": [
"net/packet/af_packet.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "5.1"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "5.1",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "5.10.265",
"versionType": "semver",
"lessThanOrEqual": "5.10.*"
},
{
"status": "unaffected",
"version": "5.15.216",
"versionType": "semver",
"lessThanOrEqual": "5.15.*"
},
{
"status": "unaffected",
"version": "6.1.183",
"versionType": "semver",
"lessThanOrEqual": "6.1.*"
},
{
"status": "unaffected",
"version": "6.6.152",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.104",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.45",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.1.9",
"versionType": "semver",
"lessThanOrEqual": "7.1.*"
},
{
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"net/packet/af_packet.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-74667
Source reference:
/cveMetadata/cveId
Publisher severity
high
Source reference: /containers/cna/metrics
- Event
- #34265 · Revision 1
- Added to Heist Feed
- Publisher date