CVE-2026-74476 (GCVE-0-2026-74476)
Vulnerability from cvelistv5
Published
2026-08-15 12:27
Modified
2026-08-23 12:47
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
veth: convert frag_list skbs before running XDP
A frag_list skb can reach veth with data_len set but nr_frags zero.
veth_convert_skb_to_xdp_buff() only converts skbs that are shared,
locked, have frags[], or do not have enough headroom. It later uses
skb_is_nonlinear() to decide whether to set XDP_FLAGS_HAS_FRAGS and
xdp_frags_size.
That exposes frag_list data to XDP as if it were stored in frags[], but
frags[] is empty. AF_XDP copy mode can then trust the bogus XDP fragment
metadata, walk an empty fragment entry, and crash in memcpy() from
__xsk_rcv().
Route non-linear skbs through skb_pp_cow_data() before exposing them to
XDP, and only advertise XDP frags when the resulting skb has frags[].
skb_copy_bits() already handles frag_list input, and skb_pp_cow_data()
builds frags[] output with skb_add_rx_frag(), which is the
representation XDP multi-buffer expects.
References
Impacted products
| Vendor | Product | Version | ||
|---|---|---|---|---|
| Linux | Linux |
Version: 718a18a0c8a67f97781e40bdef7cdd055c430996 Version: 718a18a0c8a67f97781e40bdef7cdd055c430996 Version: 718a18a0c8a67f97781e40bdef7cdd055c430996 Version: 718a18a0c8a67f97781e40bdef7cdd055c430996 Version: 718a18a0c8a67f97781e40bdef7cdd055c430996 Version: 718a18a0c8a67f97781e40bdef7cdd055c430996 |
||
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{
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"versionType": "original_commit_for_fix"
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"descriptions": [
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"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nveth: convert frag_list skbs before running XDP\n\nA frag_list skb can reach veth with data_len set but nr_frags zero.\nveth_convert_skb_to_xdp_buff() only converts skbs that are shared,\nlocked, have frags[], or do not have enough headroom. It later uses\nskb_is_nonlinear() to decide whether to set XDP_FLAGS_HAS_FRAGS and\nxdp_frags_size.\n\nThat exposes frag_list data to XDP as if it were stored in frags[], but\nfrags[] is empty. AF_XDP copy mode can then trust the bogus XDP fragment\nmetadata, walk an empty fragment entry, and crash in memcpy() from\n__xsk_rcv().\n\nRoute non-linear skbs through skb_pp_cow_data() before exposing them to\nXDP, and only advertise XDP frags when the resulting skb has frags[].\nskb_copy_bits() already handles frag_list input, and skb_pp_cow_data()\nbuilds frags[] output with skb_add_rx_frag(), which is the\nrepresentation XDP multi-buffer expects."
}
],
"metrics": [
{
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"baseSeverity": "CRITICAL",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H",
"version": "3.1"
},
"scenarios": [
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"lang": "en",
"value": "AV:N - The bug is hit when a received skb traverses veth XDP processing; in cloud/container deployments (e.g. Cloudflare-style edge nodes) remote traffic routed to a veth peer with XDP+AF_XDP can deliver the malformed frag_list skb without local access.\nAC:L - An attacker can reliably supply the required frag_list skb (data_len\u003e0, nr_frags=0) by transmitting from the veth peer via sockets or GRO aggregation, controlling packet size, timing, and content without depending on uncontrollable kernel state.\nPR:N - Remote exploitation needs no attacker privileges when ingress traffic reaches a veth that already has an XDP program redirecting to an AF_XDP socket; only network-delivered skbs trigger veth_convert_skb_to_xdp_buff() and the faulty __xsk_rcv() path.\nUI:N - No victim user action is required beyond normal network traffic reaching the veth interface; exploitation is automatic once a qualifying frag_list skb is received and redirected to AF_XDP copy mode.\nS:U - The flaw causes kernel memory reads and crashes within the host kernel security boundary; it does not cross VM, hypervisor, or IOMMU isolation boundaries.\nC:H - Bogus XDP_FLAGS_HAS_FRAGS metadata makes __xsk_rcv() memcpy from uninitialized frags[] entries via skb_frag_address(), enabling out-of-bounds kernel memory reads into the AF_XDP receive buffer before faulting.\nI:N - The failure mode is a kernel-side memcpy read using invalid fragment metadata; data is copied into the attacker\u0027s AF_XDP ring buffer rather than corrupting kernel or other tenants\u0027 memory for integrity purposes.\nA:H - The commit and code path confirm a kernel crash when __xsk_rcv() follows bogus fragment metadata and memcpy faults on an invalid frags[] source address, causing oops/panic and denial of service."
}
]
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"providerMetadata": {
"dateUpdated": "2026-08-23T12:47:22.315Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
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"references": [
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"url": "https://git.kernel.org/stable/c/0be3632597b8349d43a7dc4244b492dc62a05998"
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{
"url": "https://git.kernel.org/stable/c/04958dba44dc795dc79ce2fcbc117821bbbd6542"
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{
"url": "https://git.kernel.org/stable/c/5c1c15c540fc45820ce3033c319151ec891bc10a"
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{
"url": "https://git.kernel.org/stable/c/b24ba0bbffe3e23eb2f6838881c1fabcb29fb9fb"
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"url": "https://git.kernel.org/stable/c/f9c1fff857e93be709c8b52ed1a643f37bd82c66"
},
{
"url": "https://git.kernel.org/stable/c/d0d6415963040c401e7a7e4e482a698ba52448cb"
}
],
"title": "veth: convert frag_list skbs before running XDP",
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"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-74476",
"datePublished": "2026-08-15T12:27:11.309Z",
"dateReserved": "2026-08-15T05:44:03.903Z",
"dateUpdated": "2026-08-23T12:47:22.315Z",
"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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