CVE-2026-74310 (GCVE-0-2026-74310)

Vulnerability from cvelistv5 – Published: 2026-08-15 05:58 – Updated: 2026-08-17 05:45
VLAI
Title
vhost/net: complete zerocopy ubufs only once
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.
Severity
9.3 (Critical)
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: bab632d69ee48a106e779b60cc01adfe80a72807 , < ea71f873423fb73e66ad88936d6759ac0ad4aa53 (git)
Affected: bab632d69ee48a106e779b60cc01adfe80a72807 , < 6445b945024f4c7675ae5352b2d5885cb1deea71 (git)
Affected: bab632d69ee48a106e779b60cc01adfe80a72807 , < a9f8a1d2e3ff511eafd4c5462481950c2f4d2b5d (git)
Affected: bab632d69ee48a106e779b60cc01adfe80a72807 , < 321c73baf54d971ce3771fea275c98a247f7ee35 (git)
Affected: bab632d69ee48a106e779b60cc01adfe80a72807 , < c069437924663539a93a1e5afe90838d9ccee284 (git)
Affected: bab632d69ee48a106e779b60cc01adfe80a72807 , < 8f6898fe80794f2d7c3d38c1158c806e4074a1c4 (git)
guessed Create a notification for this product.
Linux Linux Affected: 3.1
Unaffected: 0 , < 3.1 (semver)
Unaffected: 6.1.178 , ≤ 6.1.* (semver)
Unaffected: 6.6.145 , ≤ 6.6.* (semver)
Unaffected: 6.12.97 , ≤ 6.12.* (semver)
Unaffected: 6.18.40 , ≤ 6.18.* (semver)
Unaffected: 7.1.5 , ≤ 7.1.* (semver)
Unaffected: 7.2 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
Show details on NVD website
To clipboard 

{
  "containers": {
    "cna": {
      "affected": [
        {
          "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"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.178",
                  "versionStartIncluding": "3.1",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.145",
                  "versionStartIncluding": "3.1",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.97",
                  "versionStartIncluding": "3.1",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.40",
                  "versionStartIncluding": "3.1",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1.5",
                  "versionStartIncluding": "3.1",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2",
                  "versionStartIncluding": "3.1",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "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."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 9.3,
            "baseSeverity": "CRITICAL",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The bug is only reachable on the vhost-net TX zerocopy path via /dev/vhost-net ioctls or virtio-net TX descriptors handled by the host vhost worker; remote wire packets do not carry vhost ubuf_info state, so no network-facing host protocol reaches vhost_zerocopy_complete().\nAC:L - Once experimental_zcopytx is enabled, an attacker can reliably send \u003e=256-byte zerocopy TX frames through a tap/veth backend so skb_zerocopy_clone/skb_copy_ubufs fires, then force backend teardown via VHOST_NET_SET_BACKEND or VM stop/migration while cloned completions remain pending.\nPR:N - A malicious KVM guest on a host using vhost-net needs no host root, capabilities, or /dev/vhost-net access\u2014only control of virtio TX descriptors and normal VM networking; a host-side attacker can also open /dev/vhost-net with only device-node permissions because drivers/vhost performs no capable() checks.\nUI:N - No victim user interaction is required beyond standard VM or vhost-net operation; the attacker directly drives virtio TX traffic, optional veth forwarding that clones zerocopy skbs, and backend reset/teardown that frees vhost_net_ubuf_ref while stale ubuf completions are still outstanding.\nS:C - In the standard KVM deployment, vhost-net is host-kernel code enforcing the guest NIC boundary; the slab use-after-free in vhost_zerocopy_complete executes in host context from guest-supplied zerocopy TX, corrupting host vhost/virtqueue state outside the guest security authority.\nC:H - This is a slab use-after-free: after premature completion frees vhost_net_ubuf_ref, a later skb_zcopy_clear callback dereferences freed ubuf-\u003ectx/ubufs memory in vhost_zerocopy_complete, giving attacker-influenced UAF primitives suitable for arbitrary kernel memory disclosure.\nI:H - The stale completion writes vq-\u003eheads[ubuf-\u003edesc].len and decrements vhost_net_ubuf_ref on freed structures; UAF heap corruption of this class is leveragable into arbitrary write and host control-flow hijacking, including potential VM-to-host privilege escalation.\nA:H - KASAN reports slab-use-after-free in vhost_zerocopy_complete during skb_copy_ubufs/veth_xmit completion; this readily causes host kernel oops or panic and can be retriggered from a virtio guest TX loop or repeated backend resets until the host or hypervisor is unavailable."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-17T05:45:42.723Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/ea71f873423fb73e66ad88936d6759ac0ad4aa53"
        },
        {
          "url": "https://git.kernel.org/stable/c/6445b945024f4c7675ae5352b2d5885cb1deea71"
        },
        {
          "url": "https://git.kernel.org/stable/c/a9f8a1d2e3ff511eafd4c5462481950c2f4d2b5d"
        },
        {
          "url": "https://git.kernel.org/stable/c/321c73baf54d971ce3771fea275c98a247f7ee35"
        },
        {
          "url": "https://git.kernel.org/stable/c/c069437924663539a93a1e5afe90838d9ccee284"
        },
        {
          "url": "https://git.kernel.org/stable/c/8f6898fe80794f2d7c3d38c1158c806e4074a1c4"
        }
      ],
      "title": "vhost/net: complete zerocopy ubufs only once",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-74310",
    "datePublished": "2026-08-15T05:58:10.043Z",
    "dateReserved": "2026-08-15T05:44:03.883Z",
    "dateUpdated": "2026-08-17T05:45:42.723Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-74310",
      "date": "2026-08-18",
      "epss": "0.0014",
      "percentile": "0.03808"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-74310\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2026-08-15T06:22:30.987\",\"lastModified\":\"2026-08-17T06:19:25.200\",\"vulnStatus\":\"Received\",\"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.\"}],\"affected\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"affectedData\":[{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"unaffected\",\"programFiles\":[\"drivers/vhost/net.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"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\",\"status\":\"affected\"}]},{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"affected\",\"programFiles\":[\"drivers/vhost/net.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"3.1\",\"status\":\"affected\"},{\"version\":\"0\",\"lessThan\":\"3.1\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.1.178\",\"lessThanOrEqual\":\"6.1.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.6.145\",\"lessThanOrEqual\":\"6.6.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.12.97\",\"lessThanOrEqual\":\"6.12.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.18.40\",\"lessThanOrEqual\":\"6.18.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.1.5\",\"lessThanOrEqual\":\"7.1.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.2\",\"lessThanOrEqual\":\"*\",\"versionType\":\"original_commit_for_fix\",\"status\":\"unaffected\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H\",\"baseScore\":9.3,\"baseSeverity\":\"CRITICAL\",\"attackVector\":\"LOCAL\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"scope\":\"CHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":2.5,\"impactScore\":6.0}]},\"references\":[{\"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\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}"
  }
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • 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.


Detection rules are retrieved from Rulezet.