vhost/net: complete zerocopy ubufs only once
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 re
CVE-2026-74310
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2026-74310
Linux
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Linux
Source reference: /containers/cna/affected/1/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "bab632d69ee48a106e779b60cc01adfe80a72807",
"lessThan": "ea71f873423fb73e66ad88936d6759ac0ad4aa53",
"versionType": "git"
},
{
"status": "affected",
"version": "bab632d69ee48a106e779b60cc01adfe80a72807",
"lessThan": "6445b945024f4c7675ae5352b2d5885cb1deea71",
"versionType": "git"
},
{
"status": "affected",
"version": "bab632d69ee48a106e779b60cc01adfe80a72807",
"lessThan": "a9f8a1d2e3ff511eafd4c5462481950c2f4d2b5d",
"versionType": "git"
},
{
"status": "affected",
"version": "bab632d69ee48a106e779b60cc01adfe80a72807",
"lessThan": "321c73baf54d971ce3771fea275c98a247f7ee35",
"versionType": "git"
},
{
"status": "affected",
"version": "bab632d69ee48a106e779b60cc01adfe80a72807",
"lessThan": "c069437924663539a93a1e5afe90838d9ccee284",
"versionType": "git"
},
{
"status": "affected",
"version": "bab632d69ee48a106e779b60cc01adfe80a72807",
"lessThan": "8f6898fe80794f2d7c3d38c1158c806e4074a1c4",
"versionType": "git"
}
],
"programFiles": [
"drivers/vhost/net.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "3.1"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "3.1",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "6.1.178",
"versionType": "semver",
"lessThanOrEqual": "6.1.*"
},
{
"status": "unaffected",
"version": "6.6.145",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.97",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.40",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.1.5",
"versionType": "semver",
"lessThanOrEqual": "7.1.*"
},
{
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"drivers/vhost/net.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-74310
Source reference:
/cveMetadata/cveId
Publisher severity
critical
Source reference: /containers/cna/metrics
- Event
- #33094 · Revision 1
- Added to Heist Feed
- Publisher date