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vhost/net: complete zerocopy ubufs only once

Type: advisorySource: Official CVE List1 source record

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

Announced Source revision 1
Original source ↗

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
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