Vulnerability-Lookup

GHSA-VF8C-HHH3-5W4X

Vulnerability from github – Published: 2026-10-28 12:31 – Updated: 2026-10-28 12:31

Details

In the Linux kernel, the following vulnerability has been resolved:

vsock/virtio: validate packet source for connected sockets

virtio_transport_recv_pkt() looks up sockets first by the full source and destination tuple, then by destination only in the bound table. The fallback is needed for listening and connecting sockets, but sockets remain in the bound table after connect(), so it can also return a non-listening socket.

The fallback does not validate the source address. In TCP_SYN_SENT, a RESPONSE from an unrelated source can transition the victim socket to TCP_ESTABLISHED while its stored remote address remains unchanged. Subsequent RW packets from that source are delivered through the same destination-only fallback.

This was reproduced with capability-empty processes under different UIDs. The attacker discovered the target tuple through unprivileged AF_VSOCK sock_diag and caused the victim socket to read 16 attacker-chosen bytes; the intended peer-side socket read 0 of those 16 bytes.

Add vsock_check_source() to validate the transport, source port and source CID against the peer stored in a non-listening socket. The local transport is the CID exception because its packets are generated internally with VMADDR_CID_LOCAL as their source, including connections using CID aliases.

Use the helper after lock_sock() in the virtio receive path.

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{
  "affected": [],
  "aliases": [
    "CVE-2026-99123"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-10-28T11:17:31Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nvsock/virtio: validate packet source for connected sockets\n\nvirtio_transport_recv_pkt() looks up sockets first by the full source and\ndestination tuple, then by destination only in the bound table. The\nfallback is needed for listening and connecting sockets, but sockets remain\nin the bound table after connect(), so it can also return a non-listening\nsocket.\n\nThe fallback does not validate the source address. In TCP_SYN_SENT, a\nRESPONSE from an unrelated source can transition the victim socket to\nTCP_ESTABLISHED while its stored remote address remains unchanged.\nSubsequent RW packets from that source are delivered through the same\ndestination-only fallback.\n\nThis was reproduced with capability-empty processes under different UIDs.\nThe attacker discovered the target tuple through unprivileged AF_VSOCK\nsock_diag and caused the victim socket to read 16 attacker-chosen bytes;\nthe intended peer-side socket read 0 of those 16 bytes.\n\nAdd vsock_check_source() to validate the transport, source port and source\nCID against the peer stored in a non-listening socket. The local transport\nis the CID exception because its packets are generated internally with\nVMADDR_CID_LOCAL as their source, including connections using CID aliases.\n\nUse the helper after lock_sock() in the virtio receive path.",
  "id": "GHSA-vf8c-hhh3-5w4x",
  "modified": "2026-10-28T12:31:04Z",
  "published": "2026-10-28T12:31:03Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-99123"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/6cd829de69efd9ed3a53aa2421004a0396eb2bd7"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/dee44f41f206becb41c492899c1996cfd7f82a1b"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/e9bf92de436ba55f33eaa55d7008e68551123cfd"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

CVE-2026-99123 (GCVE-0-2026-99123)

Vulnerability from cvelistv5 – Published: 2026-10-28 10:34 – Updated: 2026-10-28 10:34

Title

vsock/virtio: validate packet source for connected sockets

Summary

In the Linux kernel, the following vulnerability has been resolved: vsock/virtio: validate packet source for connected sockets virtio_transport_recv_pkt() looks up sockets first by the full source and destination tuple, then by destination only in the bound table. The fallback is needed for listening and connecting sockets, but sockets remain in the bound table after connect(), so it can also return a non-listening socket. The fallback does not validate the source address. In TCP_SYN_SENT, a RESPONSE from an unrelated source can transition the victim socket to TCP_ESTABLISHED while its stored remote address remains unchanged. Subsequent RW packets from that source are delivered through the same destination-only fallback. This was reproduced with capability-empty processes under different UIDs. The attacker discovered the target tuple through unprivileged AF_VSOCK sock_diag and caused the victim socket to read 16 attacker-chosen bytes; the intended peer-side socket read 0 of those 16 bytes. Add vsock_check_source() to validate the transport, source port and source CID against the peer stored in a non-listening socket. The local transport is the CID exception because its packets are generated internally with VMADDR_CID_LOCAL as their source, including connections using CID aliases. Use the helper after lock_sock() in the virtio receive path.

Severity

No CVSS data available.

Assigner

Linux CNA under the mitre root

CNA scorecard D 53/100 over 7033 records in the last 180 days details

References

3 references

URL	Tags
https://git.kernel.org/stable/c/6cd829de69efd9ed3…
https://git.kernel.org/stable/c/e9bf92de436ba55f3…
https://git.kernel.org/stable/c/dee44f41f206becb4…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 06a8fc78367d070720af960dcecec917d3ae5f3b , < 6cd829de69efd9ed3a53aa2421004a0396eb2bd7 (git) Affected: 06a8fc78367d070720af960dcecec917d3ae5f3b , < e9bf92de436ba55f33eaa55d7008e68551123cfd (git) Affected: 06a8fc78367d070720af960dcecec917d3ae5f3b , < dee44f41f206becb41c492899c1996cfd7f82a1b (git)
Linux	Linux	Affected: 4.8 Unaffected: 0 , < 4.8 (semver) Unaffected: 6.18.59 , ≤ 6.18.* (semver) Unaffected: 7.2.13 , ≤ 7.2.* (semver) Unaffected: 7.3 , ≤ * (original_commit_for_fix)

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{
  "containers": {
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      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "include/net/af_vsock.h",
            "net/vmw_vsock/af_vsock.c",
            "net/vmw_vsock/virtio_transport_common.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
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              "status": "affected",
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              "versionType": "git"
            },
            {
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              "versionType": "git"
            },
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            }
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          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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              "status": "affected",
              "version": "4.8"
            },
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              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.59",
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            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.13",
              "versionType": "semver"
            },
            {
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              "version": "7.3",
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          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nvsock/virtio: validate packet source for connected sockets\n\nvirtio_transport_recv_pkt() looks up sockets first by the full source and\ndestination tuple, then by destination only in the bound table. The\nfallback is needed for listening and connecting sockets, but sockets remain\nin the bound table after connect(), so it can also return a non-listening\nsocket.\n\nThe fallback does not validate the source address. In TCP_SYN_SENT, a\nRESPONSE from an unrelated source can transition the victim socket to\nTCP_ESTABLISHED while its stored remote address remains unchanged.\nSubsequent RW packets from that source are delivered through the same\ndestination-only fallback.\n\nThis was reproduced with capability-empty processes under different UIDs.\nThe attacker discovered the target tuple through unprivileged AF_VSOCK\nsock_diag and caused the victim socket to read 16 attacker-chosen bytes;\nthe intended peer-side socket read 0 of those 16 bytes.\n\nAdd vsock_check_source() to validate the transport, source port and source\nCID against the peer stored in a non-listening socket. The local transport\nis the CID exception because its packets are generated internally with\nVMADDR_CID_LOCAL as their source, including connections using CID aliases.\n\nUse the helper after lock_sock() in the virtio receive path."
        }
      ],
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        "dateUpdated": "2026-10-28T10:34:38.600Z",
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    "datePublished": "2026-10-28T10:34:38.600Z",
    "dateReserved": "2026-09-25T10:25:14.393Z",
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    "state": "PUBLISHED"
  },
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}

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.

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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
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