CVE-2026-64115 (GCVE-0-2026-64115)
Vulnerability from cvelistv5
Published
2026-07-19 15:40
Modified
2026-08-05 12:39
Severity ?
8.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: vsock/vmci: fix UAF when peer resets connection during handshake vmci_transport_recv_connecting_server() returned err = 0 for a peer RST in its default switch arm: err = pkt->type == VMCI_TRANSPORT_PACKET_TYPE_RST ? 0 : -EINVAL; That made vmci_transport_recv_listen() skip vsock_remove_pending(), leaving the pending socket on the listener's pending_links with sk_state = TCP_CLOSE while destroy: still dropped the explicit reference taken before schedule_delayed_work(). One second later vsock_pending_work() observed is_pending=true and performed full cleanup: vsock_remove_pending() then the two trailing sock_put(sk) calls -- the first reached refcount 0 and __sk_freed the socket, and the second wrote into the freed object: BUG: KASAN: slab-use-after-free in refcount_warn_saturate Write of size 4 at addr ffff88800b1cac80 by task kworker Workqueue: events vsock_pending_work Treat peer RST like any other unexpected packet type (err = -EINVAL). All destroy: arms now return err < 0, so vmci_transport_recv_listen() removes pending from pending_links synchronously and vsock_pending_work() takes the is_pending=false / !rejected branch, dropping only its own work reference. This also closes the multi-packet race Sashiko reported on v2: pending is removed from the list before any subsequent packet can find it. The pre-existing sk_acceptq_removed() gap on the err < 0 path of vmci_transport_recv_listen() that Sashiko also noted is not introduced or changed by this patch. Tested on lts-6.12.79 with KASAN: 52/100 unpatched -> 0/100 patched.
References
Impacted products
Vendor Product Version
Linux Linux Version: d021c344051af91f42c5ba9fdedc176740cbd238
Version: d021c344051af91f42c5ba9fdedc176740cbd238
Version: d021c344051af91f42c5ba9fdedc176740cbd238
Version: d021c344051af91f42c5ba9fdedc176740cbd238
Version: d021c344051af91f42c5ba9fdedc176740cbd238
Version: d021c344051af91f42c5ba9fdedc176740cbd238
Version: d021c344051af91f42c5ba9fdedc176740cbd238
Version: d021c344051af91f42c5ba9fdedc176740cbd238
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/vmw_vsock/vmci_transport.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
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          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
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          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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              "version": "3.9"
            },
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              "version": "0",
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              "version": "5.10.258",
              "versionType": "semver"
            },
            {
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              "status": "unaffected",
              "version": "5.15.209",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.175",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.142",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.92",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.34",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.0.*",
              "status": "unaffected",
              "version": "7.0.11",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
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                  "versionEndExcluding": "5.10.258",
                  "versionStartIncluding": "3.9",
                  "vulnerable": true
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              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nvsock/vmci: fix UAF when peer resets connection during handshake\n\nvmci_transport_recv_connecting_server() returned err = 0 for a peer\nRST in its default switch arm:\n\n\terr = pkt-\u003etype == VMCI_TRANSPORT_PACKET_TYPE_RST ? 0 : -EINVAL;\n\nThat made vmci_transport_recv_listen() skip vsock_remove_pending(),\nleaving the pending socket on the listener\u0027s pending_links with\nsk_state = TCP_CLOSE while destroy: still dropped the explicit\nreference taken before schedule_delayed_work().\n\nOne second later vsock_pending_work() observed is_pending=true and\nperformed full cleanup: vsock_remove_pending() then the two trailing\nsock_put(sk) calls -- the first reached refcount 0 and __sk_freed\nthe socket, and the second wrote into the freed object:\n\n  BUG: KASAN: slab-use-after-free in refcount_warn_saturate\n  Write of size 4 at addr ffff88800b1cac80 by task kworker\n  Workqueue: events vsock_pending_work\n\nTreat peer RST like any other unexpected packet type (err = -EINVAL).\nAll destroy: arms now return err \u003c 0, so vmci_transport_recv_listen()\nremoves pending from pending_links synchronously and\nvsock_pending_work() takes the is_pending=false / !rejected branch,\ndropping only its own work reference.  This also closes the\nmulti-packet race Sashiko reported on v2: pending is removed from\nthe list before any subsequent packet can find it.\n\nThe pre-existing sk_acceptq_removed() gap on the err \u003c 0 path of\nvmci_transport_recv_listen() that Sashiko also noted is not\nintroduced or changed by this patch.\n\nTested on lts-6.12.79 with KASAN: 52/100 unpatched -\u003e 0/100 patched."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 8.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - Exploitation requires local AF_VSOCK syscalls (connect/close) to drive VMCI control packets; per kernel CVSS guidance, vsock is scored Local even when the peer is a VM guest reaching a host listener.\nAC:L - The attacker controls both sides of the handshake race by initiating a connection and aborting it with RST during TCP_SYN_SENT; KASAN testing showed 52/100 repro without conditions outside attacker control.\nPR:L - Any unprivileged local user inside a VM (or on the same host) can open AF_VSOCK sockets and connect to a listening peer without CAP_NET_ADMIN or other elevated privileges.\nUI:N - Exploitation requires only a victim service with a bound/listening vsock socket, which is normal background operation; no interactive victim action is needed.\nS:C - In the most severe reasonable VMware deployment, an unprivileged guest VM triggers kernel memory corruption on the hypervisor host via VMCI vsock, crossing the guest-to-host virtualisation security boundary analogous to KVM/Xen VM escape.\nC:H - The bug is a slab use-after-free on struct sock; UAF on kernel heap objects enables arbitrary memory read primitives through controlled reuse of the freed socket structure.\nI:H - The UAF involves a write to a freed object\u0027s refcount field and corrupts kernel heap metadata, providing a foundation for arbitrary write and kernel code execution via heap grooming.\nA:H - The vulnerability reliably triggers kernel UAF detected by KASAN (refcount write to freed memory on a kworker), which causes kernel oops/panic and denial of host availability."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T12:39:24.360Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/1e19f08552b90070ed18bafb1763c78297823af6"
        },
        {
          "url": "https://git.kernel.org/stable/c/1dd531e28f61edd286edc486ab068f135b5ae1eb"
        },
        {
          "url": "https://git.kernel.org/stable/c/ecda37f8faab3220da199335e42564cb7a9ad145"
        },
        {
          "url": "https://git.kernel.org/stable/c/cc27e989a5dfdfcfc1cca7c3be27a0c7532b46cb"
        },
        {
          "url": "https://git.kernel.org/stable/c/47e63077605c6c2aa45b3df9847a8cdc1f1f6ef9"
        },
        {
          "url": "https://git.kernel.org/stable/c/440447699c681e26ed58e9c309cad718270a18b4"
        },
        {
          "url": "https://git.kernel.org/stable/c/9fe74e42914c851d68069713b7b917a9c33faf26"
        },
        {
          "url": "https://git.kernel.org/stable/c/99e22ddf4edb63dc8382bc028af928056d3450cf"
        }
      ],
      "title": "vsock/vmci: fix UAF when peer resets connection during handshake",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-64115",
    "datePublished": "2026-07-19T15:40:15.513Z",
    "dateReserved": "2026-07-19T07:54:57.035Z",
    "dateUpdated": "2026-08-05T12:39:24.360Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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