CVE-2026-72407 (GCVE-0-2026-72407)
Vulnerability from cvelistv5
Published
2026-08-15 05:56
Modified
2026-08-17 05:43
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
geneve: validate inner network offset in geneve_gro_complete()
Even with both paths gated on gs->gro_hint, geneve_gro_complete()
re-derives the inner dispatch type and length from the packet and the
current gs->gro_hint, independently of geneve_gro_receive(). The two can
disagree if gs->gro_hint flips under a concurrent geneve_quiesce()/
geneve_unquiesce() (sk_user_data is NULL across a synchronize_net()), or if
the re-read option bytes differ from the ones receive parsed.
geneve_gro_receive() already records the inner network header position in
NAPI_GRO_CB()->inner_network_offset. Have geneve_gro_complete() compute the
offset it is about to dispatch at, adding ETH_HLEN in the ETH_P_TEB case
where eth_gro_complete() steps over the inner MAC header, and bail out if
it lands past inner_network_offset.
Use a lower bound rather than exact equality: between gh_len and the inner
L3 header, geneve_gro_receive() may also have pulled an inner VLAN tag
(vlan_gro_receive() advances the recorded offset past it), which only moves
inner_network_offset further out. A valid frame therefore always satisfies
inner_nh <= inner_network_offset, while a gh_len inflated by a hint
gro_receive() did not honour dispatches past the validated inner header,
i.e. the out-of-bounds completion. Only the latter is rejected.
References
Impacted products
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"drivers/net/geneve.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
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"status": "affected",
"version": "fd0dd796576e1a560e1441e665810129f0a82be0",
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{
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"product": "Linux",
"programFiles": [
"drivers/net/geneve.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "7.0"
},
{
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"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
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"status": "unaffected",
"version": "7.1.5",
"versionType": "semver"
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{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix"
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"versionStartIncluding": "7.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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}
],
"negate": false,
"operator": "OR"
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"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\ngeneve: validate inner network offset in geneve_gro_complete()\n\nEven with both paths gated on gs-\u003egro_hint, geneve_gro_complete()\nre-derives the inner dispatch type and length from the packet and the\ncurrent gs-\u003egro_hint, independently of geneve_gro_receive(). The two can\ndisagree if gs-\u003egro_hint flips under a concurrent geneve_quiesce()/\ngeneve_unquiesce() (sk_user_data is NULL across a synchronize_net()), or if\nthe re-read option bytes differ from the ones receive parsed.\n\ngeneve_gro_receive() already records the inner network header position in\nNAPI_GRO_CB()-\u003einner_network_offset. Have geneve_gro_complete() compute the\noffset it is about to dispatch at, adding ETH_HLEN in the ETH_P_TEB case\nwhere eth_gro_complete() steps over the inner MAC header, and bail out if\nit lands past inner_network_offset.\n\nUse a lower bound rather than exact equality: between gh_len and the inner\nL3 header, geneve_gro_receive() may also have pulled an inner VLAN tag\n(vlan_gro_receive() advances the recorded offset past it), which only moves\ninner_network_offset further out. A valid frame therefore always satisfies\ninner_nh \u003c= inner_network_offset, while a gh_len inflated by a hint\ngro_receive() did not honour dispatches past the validated inner header,\ni.e. the out-of-bounds completion. Only the latter is rejected."
}
],
"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:H",
"version": "3.1"
},
"scenarios": [
{
"lang": "en",
"value": "AV:N - The bug is in geneve_gro_complete() on the NAPI GRO receive path for UDP-encapsulated GENEVE frames; a remote peer can deliver crafted packets to a listening GENEVE UDP port on cloud/overlay hosts without local access.\nAC:L - An attacker can reliably trigger the mismatch by flooding GRO-eligible GENEVE frames with crafted GRO-hint options and timing them against geneve_quiesce()/geneve_unquiesce() during changelink, or self-trigger that race with CAP_NET_ADMIN in a user namespace.\nPR:N - Exploitation requires no credentials or capabilities on the victim; the attacker only needs network reachability to a host already running a gro_hint-enabled GENEVE tunnel, which is common on overlay networks.\nUI:N - Exploitation is fully automated through malicious network traffic and does not require any victim user action such as mounting filesystems or opening files.\nS:C - On cloud/overlay deployments a tenant VM or remote overlay peer can corrupt the hypervisor/host kernel through underlay GENEVE GRO processing, crossing the guest/host security boundary.\nC:H - When gro_complete() dispatches past inner_network_offset, eth_gro_complete() and inet_gro_complete() read headers from attacker-influenced out-of-bounds skb memory, enabling arbitrary kernel memory disclosure.\nI:H - The same out-of-bounds gro_complete dispatch writes header fields (e.g., iph-\u003etot_len and iph-\u003echeck in inet_gro_complete()), causing memory corruption that can be leveraged for arbitrary write or code execution.\nA:H - Out-of-bounds GRO completion can cause kernel oops/panic or forced skb drop under error paths, enabling repeatable remote denial of service against the host."
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-08-17T05:43:47.398Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
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"references": [
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"url": "https://git.kernel.org/stable/c/e2087447f562692ff0cd08a0554d8d4ad083aa5c"
},
{
"url": "https://git.kernel.org/stable/c/cbb0d30a1ad6fc9439b1dc9b4f5a7a9140d3b11f"
}
],
"title": "geneve: validate inner network offset in geneve_gro_complete()",
"x_generator": {
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"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-72407",
"datePublished": "2026-08-15T05:56:30.847Z",
"dateReserved": "2026-08-09T03:40:39.926Z",
"dateUpdated": "2026-08-17T05:43:47.398Z",
"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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