flow_dissector: check device type before reading ETH_ADDRS
In the Linux kernel, the following vulnerability has been resolved: flow_dissector: check device type before reading ETH_ADDRS __skb_flow_dissect() unconditionally reads 12 bytes from eth_hdr(skb) when FLOW_DISSECTOR_KEY_ETH_ADDRS is requested. This assumes the skb has a valid Ethernet header at mac_header, which is not always the case. The problem can be triggered by: 1. Creating a TUN device in L3 mode (IFF_TUN, hard_header_len=0) 2. Attaching a multiq qdisc with a flower filter matching on eth_src 3. Sending a packet through AF_PACKET Since TUN in L3 mode has no link-layer header, mac_header points to the L3 data area. The flow dissector reads 12 bytes of uninitialized skb memory, which then propagates through fl_set_masked_key() and is used as a rhashtable lookup key in __fl_lookup(), as reported by KMSAN. Rejecting the filter in the control path (at tc filter add time) is not feasible because TC filter blocks can be shared between arbitrary devices -- a filter installed on an Ethernet device may later classify packets on a headerless device through a shared block. The device association is not fixed at filter creation time. Fix this by gating the memcpy on dev->type == ARPHRD_ETHER, which ensures only true Ethernet-framed packets have their addresses read. This is more precise than the previous hard_header_len >= 12 check, which would incorrectly pass for non-Ethernet link types like IPoIB (ARPHRD_INFINIBAND, hard_header_len=24) and FDDI (hard_header_len=21) whose L2 hea
CVE-2026-72444
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-2026-72444
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": "67a900cc0436d74e7ff89042371760def087680d",
"lessThan": "0fe6455b8e1a22414f39c07bc90a1df12b52ec74",
"versionType": "git"
},
{
"status": "affected",
"version": "67a900cc0436d74e7ff89042371760def087680d",
"lessThan": "9a65860959db594dfc1820c7fdc09285fb7556bf",
"versionType": "git"
},
{
"status": "affected",
"version": "67a900cc0436d74e7ff89042371760def087680d",
"lessThan": "594c90b197141944f25991b8314de5c26ee27a7e",
"versionType": "git"
},
{
"status": "affected",
"version": "67a900cc0436d74e7ff89042371760def087680d",
"lessThan": "c6d3bcb0f934d4297ac5fa1c8656ae40694fb601",
"versionType": "git"
},
{
"status": "affected",
"version": "67a900cc0436d74e7ff89042371760def087680d",
"lessThan": "825de39f0c35a112148799b3cbe45af3766c018a",
"versionType": "git"
},
{
"status": "affected",
"version": "67a900cc0436d74e7ff89042371760def087680d",
"lessThan": "bf6e8af2c8be77489bedeae9f8a9654cb710e500",
"versionType": "git"
}
],
"programFiles": [
"net/core/flow_dissector.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "4.2"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "4.2",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "6.1.178",
"versionType": "semver",
"lessThanOrEqual": "6.1.*"
},
{
"status": "unaffected",
"version": "6.6.145",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.97",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.40",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.1.5",
"versionType": "semver",
"lessThanOrEqual": "7.1.*"
},
{
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"net/core/flow_dissector.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-72444
Source reference:
/cveMetadata/cveId
Publisher severity
high
Source reference: /containers/cna/metrics
- Event
- #33054 · Revision 1
- Added to Heist Feed
- Publisher date