FKIE_CVE-2026-74310
Vulnerability from fkie_nvd - Published: 2026-08-15 06:22 - Updated: 2026-10-16 19:17
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved:
vhost/net: complete zerocopy ubufs only once
vhost-net initializes one ubuf_info per outstanding zerocopy TX
descriptor and hands it to the backend socket. The networking stack may
then clone a zerocopy skb before all skb references are released. For
example, batman-adv fragmentation reaches skb_split(), which calls
skb_zerocopy_clone() and increments the same ubuf_info refcount.
vhost_zerocopy_complete() currently treats every ubuf callback as a
completed vhost descriptor. It dereferences ubuf->ctx, writes the
descriptor completion state, and drops the vhost_net_ubuf_ref even when
the callback only releases a cloned skb reference. A backend reset can
therefore wait for and free the vhost_net_ubuf_ref while another cloned
skb still carries the same ubuf_info. A later completion then
dereferences the freed ubufs pointer.
KASAN reports the stale completion as:
BUG: KASAN: slab-use-after-free in vhost_zerocopy_complete+0x1d7/0x1f0
BUG: KASAN: slab-use-after-free in vhost_zerocopy_complete+0x101/0x1f0
vhost_zerocopy_complete
skb_copy_ubufs
__dev_forward_skb2
veth_xmit
The freed object was allocated from vhost_net_ioctl() while setting the
backend and freed through kfree_rcu()/kvfree_rcu_bulk after backend
removal, while delayed skb completion still reached
vhost_zerocopy_complete().
Honor the generic ubuf_info refcount before touching vhost state, and run
the vhost descriptor completion only for the final ubuf reference. This
matches the msg_zerocopy_complete() ownership rule for cloned zerocopy
skbs.
References
Impacted products
| Vendor | Product | Version |
|---|
{
"affected": [
{
"affectedData": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"drivers/vhost/net.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "ea71f873423fb73e66ad88936d6759ac0ad4aa53",
"status": "affected",
"version": "bab632d69ee48a106e779b60cc01adfe80a72807",
"versionType": "git"
},
{
"lessThan": "6445b945024f4c7675ae5352b2d5885cb1deea71",
"status": "affected",
"version": "bab632d69ee48a106e779b60cc01adfe80a72807",
"versionType": "git"
},
{
"lessThan": "a9f8a1d2e3ff511eafd4c5462481950c2f4d2b5d",
"status": "affected",
"version": "bab632d69ee48a106e779b60cc01adfe80a72807",
"versionType": "git"
},
{
"lessThan": "321c73baf54d971ce3771fea275c98a247f7ee35",
"status": "affected",
"version": "bab632d69ee48a106e779b60cc01adfe80a72807",
"versionType": "git"
},
{
"lessThan": "c069437924663539a93a1e5afe90838d9ccee284",
"status": "affected",
"version": "bab632d69ee48a106e779b60cc01adfe80a72807",
"versionType": "git"
},
{
"lessThan": "8f6898fe80794f2d7c3d38c1158c806e4074a1c4",
"status": "affected",
"version": "bab632d69ee48a106e779b60cc01adfe80a72807",
"versionType": "git"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"drivers/vhost/net.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "3.1"
},
{
"lessThan": "3.1",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"version": "6.1.178",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.145",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.97",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.40",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.1.*",
"status": "unaffected",
"version": "7.1.5",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix"
}
]
}
],
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nvhost/net: complete zerocopy ubufs only once\n\nvhost-net initializes one ubuf_info per outstanding zerocopy TX\ndescriptor and hands it to the backend socket. The networking stack may\nthen clone a zerocopy skb before all skb references are released. For\nexample, batman-adv fragmentation reaches skb_split(), which calls\nskb_zerocopy_clone() and increments the same ubuf_info refcount.\n\nvhost_zerocopy_complete() currently treats every ubuf callback as a\ncompleted vhost descriptor. It dereferences ubuf-\u003ectx, writes the\ndescriptor completion state, and drops the vhost_net_ubuf_ref even when\nthe callback only releases a cloned skb reference. A backend reset can\ntherefore wait for and free the vhost_net_ubuf_ref while another cloned\nskb still carries the same ubuf_info. A later completion then\ndereferences the freed ubufs pointer.\n\nKASAN reports the stale completion as:\n\n BUG: KASAN: slab-use-after-free in vhost_zerocopy_complete+0x1d7/0x1f0\n BUG: KASAN: slab-use-after-free in vhost_zerocopy_complete+0x101/0x1f0\n vhost_zerocopy_complete\n skb_copy_ubufs\n __dev_forward_skb2\n veth_xmit\n\nThe freed object was allocated from vhost_net_ioctl() while setting the\nbackend and freed through kfree_rcu()/kvfree_rcu_bulk after backend\nremoval, while delayed skb completion still reached\nvhost_zerocopy_complete().\n\nHonor the generic ubuf_info refcount before touching vhost state, and run\nthe vhost descriptor completion only for the final ubuf reference. This\nmatches the msg_zerocopy_complete() ownership rule for cloned zerocopy\nskbs."
}
],
"id": "CVE-2026-74310",
"lastModified": "2026-10-16T19:17:38.347",
"metrics": {
"cvssMetricV31": [
{
"cvssData": {
"attackComplexity": "LOW",
"attackVector": "LOCAL",
"availabilityImpact": "HIGH",
"baseScore": 9.3,
"baseSeverity": "CRITICAL",
"confidentialityImpact": "HIGH",
"integrityImpact": "HIGH",
"privilegesRequired": "NONE",
"scope": "CHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H",
"version": "3.1"
},
"exploitabilityScore": 2.5,
"impactScore": 6.0,
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"type": "Secondary"
}
],
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"id": "CVE-2026-74310",
"options": [
{
"exploitation": "none"
},
{
"automatable": "no"
},
{
"technicalImpact": "total"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-10-16T18:52:56.702664Z",
"version": "2.0.3"
}
}
]
},
"published": "2026-08-15T06:22:30.987",
"references": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/321c73baf54d971ce3771fea275c98a247f7ee35"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/6445b945024f4c7675ae5352b2d5885cb1deea71"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/8f6898fe80794f2d7c3d38c1158c806e4074a1c4"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/a9f8a1d2e3ff511eafd4c5462481950c2f4d2b5d"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/c069437924663539a93a1e5afe90838d9ccee284"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/ea71f873423fb73e66ad88936d6759ac0ad4aa53"
}
],
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"vulnStatus": "Received"
}
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Browse all ATT&CK techniques and the vulnerabilities related to each.
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