CVE-2026-72408 (GCVE-0-2026-72408)
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: gate GRO hint in geneve_gro_complete() on gs->gro_hint
geneve_gro_receive() reads the GRO hint through geneve_sk_gro_hint_off(),
which honours it only when the socket enabled IFLA_GENEVE_GRO_HINT
(gs->gro_hint). geneve_gro_complete() instead calls the low-level
geneve_opt_gro_hint_off() and acts on the hint unconditionally.
On a tunnel without the hint, receive aggregates the frames as plain
ETH_P_TEB while complete still honours an attacker-supplied hint option: it
inflates gh_len by gro_hint->nested_hdr_len (u8) and redirects the dispatch
type, so the inner gro_complete handler runs at nhoff + gh_len, an offset
receive never pulled nor validated, reading out of bounds of the skb head:
BUG: KASAN: slab-out-of-bounds in ipv6_gro_complete (net/ipv6/ip6_offload.c:196)
Read of size 1 at addr ffff88800fe91980 by task exploit/153
ipv6_gro_complete (net/ipv6/ip6_offload.c:196)
geneve_gro_complete (drivers/net/geneve.c:965)
udp_gro_complete (net/ipv4/udp_offload.c:940)
inet_gro_complete (net/ipv4/af_inet.c:1621)
__gro_flush (net/core/gro.c:306)
Gate the complete path on gs->gro_hint too via geneve_sk_gro_hint_off(), so
both paths agree. Tunnels that enable the hint are unaffected.
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": [
{
"lessThan": "49c2e7c0a69999a75ef5eaebe1559a20d0b3c15a",
"status": "affected",
"version": "fd0dd796576e1a560e1441e665810129f0a82be0",
"versionType": "git"
},
{
"lessThan": "2651c174445884ac9e85622aeade9c1f7b98d8e5",
"status": "affected",
"version": "fd0dd796576e1a560e1441e665810129f0a82be0",
"versionType": "git"
}
]
},
{
"defaultStatus": "affected",
"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"
},
{
"lessThan": "7.0",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.1.*",
"status": "unaffected",
"version": "7.1.5",
"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": "7.1.5",
"versionStartIncluding": "7.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.2",
"versionStartIncluding": "7.0",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\ngeneve: gate GRO hint in geneve_gro_complete() on gs-\u003egro_hint\n\ngeneve_gro_receive() reads the GRO hint through geneve_sk_gro_hint_off(),\nwhich honours it only when the socket enabled IFLA_GENEVE_GRO_HINT\n(gs-\u003egro_hint). geneve_gro_complete() instead calls the low-level\ngeneve_opt_gro_hint_off() and acts on the hint unconditionally.\n\nOn a tunnel without the hint, receive aggregates the frames as plain\nETH_P_TEB while complete still honours an attacker-supplied hint option: it\ninflates gh_len by gro_hint-\u003enested_hdr_len (u8) and redirects the dispatch\ntype, so the inner gro_complete handler runs at nhoff + gh_len, an offset\nreceive never pulled nor validated, reading out of bounds of the skb head:\n\n BUG: KASAN: slab-out-of-bounds in ipv6_gro_complete (net/ipv6/ip6_offload.c:196)\n Read of size 1 at addr ffff88800fe91980 by task exploit/153\n ipv6_gro_complete (net/ipv6/ip6_offload.c:196)\n geneve_gro_complete (drivers/net/geneve.c:965)\n udp_gro_complete (net/ipv4/udp_offload.c:940)\n inet_gro_complete (net/ipv4/af_inet.c:1621)\n __gro_flush (net/core/gro.c:306)\n\nGate the complete path on gs-\u003egro_hint too via geneve_sk_gro_hint_off(), so\nboth paths agree. Tunnels that enable the hint are unaffected."
}
],
"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 triggered by remotely delivered UDP/GENEVE packets processed in the NAPI GRO completion path (udp_gro_complete \u2192 geneve_gro_complete \u2192 __gro_flush), not via local syscalls or physical interfaces.\nAC:L - The attacker controls all packet fields (GRO hint option, nested_hdr_len, inner_proto_id) and can send multiple matching datagrams to force GRO aggregation/flush; no uncontrollable race or memory layout is required.\nPR:N - No authentication or local privileges are needed; any remote host that can send UDP to a victim\u0027s GENEVE tunnel port triggers the flaw on default tunnels without IFLA_GENEVE_GRO_HINT enabled.\nUI:N - Exploitation requires only transmission of crafted network packets; no victim interaction such as opening files, mounting filesystems, or clicking links is needed.\nS:C - In cloud/Kubernetes overlay deployments using GENEVE, a malicious tenant VM or pod can attack the host/hypervisor kernel over the underlay network, crossing the tenant-to-host security boundary.\nC:H - geneve_gro_complete() honors attacker-supplied GRO hint options that gro_receive() ignored, inflating gh_len and dispatching inner gro_complete past validated skb data, causing slab out-of-bounds reads and enabling arbitrary kernel memory disclosure.\nI:H - Misdirected gro_complete handlers (e.g., ipv6_gro_complete) read and rewrite protocol header fields at attacker-chosen offsets beyond the skb head, providing out-of-bounds write primitives exploitable for control-flow hijacking.\nA:H - The vulnerability provokes KASAN slab-out-of-bounds faults and kernel oops during GRO flush; repeated remote triggering can panic or hang the host, denying availability to all workloads."
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-08-17T05:43:48.541Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/49c2e7c0a69999a75ef5eaebe1559a20d0b3c15a"
},
{
"url": "https://git.kernel.org/stable/c/2651c174445884ac9e85622aeade9c1f7b98d8e5"
}
],
"title": "geneve: gate GRO hint in geneve_gro_complete() on gs-\u003egro_hint",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-72408",
"datePublished": "2026-08-15T05:56:31.477Z",
"dateReserved": "2026-08-09T03:40:39.926Z",
"dateUpdated": "2026-08-17T05:43:48.541Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
Loading…
Loading…
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.
Loading…
Loading…