CVE-2026-74475 (GCVE-0-2026-74475)
Vulnerability from cvelistv5
Published
2026-08-15 12:27
Modified
2026-08-19 16:37
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
vxlan: use neigh_ha_snapshot() in route_shortcircuit()
The neighbour hardware address n->ha can be updated asynchronously by the
neighbour subsystem, protected by n->ha_lock seqlock. Reading n->ha without
holding the seqlock loop can lead to torn reads or reading a partially updated
MAC address.
Use neigh_ha_snapshot() in route_shortcircuit() to safely copy n->ha under
read_seqbegin()/read_seqretry() lock protection before using it.
Note that arp_reduce() and neigh_reduce() seem to have the same issue
left for future patches.
References
Impacted products
| Vendor | Product | Version | ||
|---|---|---|---|---|
| Linux | Linux |
Version: e4f67addf158f98f8197e08974966b18480dc751 Version: e4f67addf158f98f8197e08974966b18480dc751 Version: e4f67addf158f98f8197e08974966b18480dc751 Version: e4f67addf158f98f8197e08974966b18480dc751 Version: e4f67addf158f98f8197e08974966b18480dc751 Version: e4f67addf158f98f8197e08974966b18480dc751 Version: e4f67addf158f98f8197e08974966b18480dc751 Version: e4f67addf158f98f8197e08974966b18480dc751 |
||
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"drivers/net/vxlan/vxlan_core.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "32a9590a8d30426e3db63e6b20893e47e02576c0",
"status": "affected",
"version": "e4f67addf158f98f8197e08974966b18480dc751",
"versionType": "git"
},
{
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"status": "affected",
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"versionType": "git"
},
{
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},
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}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"drivers/net/vxlan/vxlan_core.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "3.8"
},
{
"lessThan": "3.8",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.10.*",
"status": "unaffected",
"version": "5.10.265",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.15.*",
"status": "unaffected",
"version": "5.15.216",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"version": "6.1.183",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.151",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.103",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.44",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.1.*",
"status": "unaffected",
"version": "7.1.8",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "5.10.265",
"versionStartIncluding": "3.8",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "5.15.216",
"versionStartIncluding": "3.8",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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},
{
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"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.12.103",
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"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.18.44",
"versionStartIncluding": "3.8",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.1.8",
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"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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"versionStartIncluding": "3.8",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nvxlan: use neigh_ha_snapshot() in route_shortcircuit()\n\nThe neighbour hardware address n-\u003eha can be updated asynchronously by the\nneighbour subsystem, protected by n-\u003eha_lock seqlock. Reading n-\u003eha without\nholding the seqlock loop can lead to torn reads or reading a partially updated\nMAC address.\n\nUse neigh_ha_snapshot() in route_shortcircuit() to safely copy n-\u003eha under\nread_seqbegin()/read_seqretry() lock protection before using it.\n\nNote that arp_reduce() and neigh_reduce() seem to have the same issue\nleft for future patches."
}
],
"metrics": [
{
"cvssV3_1": {
"baseScore": 10,
"baseSeverity": "CRITICAL",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:L",
"version": "3.1"
},
"scenarios": [
{
"lang": "en",
"value": "AV:N - route_shortcircuit() runs on the vxlan_xmit() transmit path when overlay IP/IPv6 traffic is encapsulated; in cloud/SDN VTEP deployments a remote tenant can drive dev_queue_xmit() through bridge/IP forwarding without any local syscall or netlink access.\nAC:L - The attacker controls both sides of the race by concurrently sending overlay traffic that hits route_shortcircuit() and generating neighbour ha updates (ARP/NDP churn); repeated attempts do not depend on victim state or uncontrollable memory layout.\nPR:N - Exploitation requires only the ability to send overlay/underlay packets to a VTEP that already has VXLAN_F_RSC and router FDB entries configured by infrastructure; no CAP_NET_ADMIN, root, or host credentials are needed on the victim.\nUI:N - Triggering is automatic during kernel packet forwarding and VXLAN encapsulation once matching traffic flows; no mount, file open, or other victim action is required beyond normal overlay operation.\nS:C - A torn n-\u003eha read can rewrite the skb Ethernet destination and reselect a different FDB remote, mis-encapsulating traffic to an unintended VXLAN peer and crossing intended multi-tenant overlay segmentation boundaries beyond the local VTEP authority.\nC:H - Unsynchronized reads of neighbour ha during concurrent updates yield torn MAC values that drive post-rewrite FDB lookup and encapsulation, potentially delivering other tenants\u0027 overlay frames to an attacker-controlled remote endpoint or leaking mixed neighbour state.\nI:H - The corrupted hardware address is copied into the skb Ethernet header and steers subsequent vxlan_find_mac_tx()/vxlan_xmit_one() encapsulation, enabling deterministic overlay traffic redirection or injection toward an attacker-chosen VTEP rather than the intended router destination.\nA:L - While the host kernel does not panic, torn MAC rewriting can cause mis-encapsulation, FDB misses, and dropped or misdelivered overlay packets, producing intermittent connectivity loss and performance degradation on affected VTEP nodes under sustained attack."
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-08-19T16:37:28.096Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/32a9590a8d30426e3db63e6b20893e47e02576c0"
},
{
"url": "https://git.kernel.org/stable/c/d0993fc053f29e15cc7c9fe2029df3882a2ab5ab"
},
{
"url": "https://git.kernel.org/stable/c/87210054bad82bbae6f483a742dc45722fb47a6b"
},
{
"url": "https://git.kernel.org/stable/c/d08e8ac13f2e228cc7fc3c70b5ebe71557b624a0"
},
{
"url": "https://git.kernel.org/stable/c/ec341bb76d77b4c2948764375ee6bfeef4bb41c3"
},
{
"url": "https://git.kernel.org/stable/c/ff89415d34c3ab9f5312316423122e664ed3524f"
},
{
"url": "https://git.kernel.org/stable/c/05f2987f73daa05333fd713d05546142f9f7c5f0"
},
{
"url": "https://git.kernel.org/stable/c/8eca411347e1d38964f9ed2c8d3b6ab0e7e4473d"
}
],
"title": "vxlan: use neigh_ha_snapshot() in route_shortcircuit()",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-74475",
"datePublished": "2026-08-15T12:27:10.685Z",
"dateReserved": "2026-08-15T05:44:03.903Z",
"dateUpdated": "2026-08-19T16:37:28.096Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
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