GHSA-P72R-VMH2-4XJ6
Vulnerability from github – Published: 2026-08-15 15:30 – Updated: 2026-08-17 06:33In 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.
{
"affected": [],
"aliases": [
"CVE-2026-74476"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-08-15T13:17:52Z",
"severity": "CRITICAL"
},
"details": "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.",
"id": "GHSA-p72r-vmh2-4xj6",
"modified": "2026-08-17T06:33:48Z",
"published": "2026-08-15T15:30:33Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-74476"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/5c1c15c540fc45820ce3033c319151ec891bc10a"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/b24ba0bbffe3e23eb2f6838881c1fabcb29fb9fb"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/d0d6415963040c401e7a7e4e482a698ba52448cb"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/f9c1fff857e93be709c8b52ed1a643f37bd82c66"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H",
"type": "CVSS_V3"
}
]
}
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
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- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.