GHSA-9MPH-4HQC-XQX7

Vulnerability from github – Published: 2026-06-25 09:31 – Updated: 2026-06-28 09:31
VLAI
Details

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

net: guard timestamp cmsgs to real error queue skbs

skb_is_err_queue() treats PACKET_OUTGOING as the sole marker for an skb from sk_error_queue. That assumption is not true for AF_PACKET sockets: outgoing packet taps are also delivered to packet sockets with skb->pkt_type == PACKET_OUTGOING, but their skb->cb is owned by AF_PACKET instead of struct sock_exterr_skb.

If such an skb is received with timestamping enabled, the generic timestamp cmsg path can read AF_PACKET control-buffer state as sock_exterr_skb::opt_stats. With SO_RXQ_OVFL enabled, the packet drop counter overlaps opt_stats. An odd drop count makes the path emit SCM_TIMESTAMPING_OPT_STATS with skb->len and skb->data. For non-linear skbs this copies past the linear head and can trigger hardened usercopy or disclose adjacent heap contents.

Keep skb_is_err_queue() local to net/socket.c, but make it verify that the PACKET_OUTGOING marker is paired with the sock_rmem_free destructor installed by sock_queue_err_skb(). AF_PACKET receive skbs use normal receive ownership and no longer pass as error-queue skbs, while legitimate sk_error_queue entries keep the PACKET_OUTGOING marker and sock_rmem_free ownership.

Severity
7.1 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
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{
  "affected": [],
  "aliases": [
    "CVE-2026-53223"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-06-25T09:16:40Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: guard timestamp cmsgs to real error queue skbs\n\nskb_is_err_queue() treats PACKET_OUTGOING as the sole marker for an skb\nfrom sk_error_queue. That assumption is not true for AF_PACKET sockets:\noutgoing packet taps are also delivered to packet sockets with\nskb-\u003epkt_type == PACKET_OUTGOING, but their skb-\u003ecb is owned by AF_PACKET\ninstead of struct sock_exterr_skb.\n\nIf such an skb is received with timestamping enabled, the generic\ntimestamp cmsg path can read AF_PACKET control-buffer state as\nsock_exterr_skb::opt_stats. With SO_RXQ_OVFL enabled, the packet drop\ncounter overlaps opt_stats. An odd drop count makes the path emit\nSCM_TIMESTAMPING_OPT_STATS with skb-\u003elen and skb-\u003edata. For non-linear\nskbs this copies past the linear head and can trigger hardened usercopy or\ndisclose adjacent heap contents.\n\nKeep skb_is_err_queue() local to net/socket.c, but make it verify that\nthe PACKET_OUTGOING marker is paired with the sock_rmem_free destructor\ninstalled by sock_queue_err_skb(). AF_PACKET receive skbs use normal\nreceive ownership and no longer pass as error-queue skbs, while legitimate\nsk_error_queue entries keep the PACKET_OUTGOING marker and sock_rmem_free\nownership.",
  "id": "GHSA-9mph-4hqc-xqx7",
  "modified": "2026-06-28T09:31:45Z",
  "published": "2026-06-25T09:31:21Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-53223"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/1ee90b77b727df903033db873c75caac5c27ec98"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/24a0d548d3a765cd4558224e4f8e06e14cba26e3"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/3dde4fb941fa5649ab809f6cd3e20e0c424a4e31"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/71ff5cdd5da61d0438e902aa0fd68c28bc901abe"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ad9a0374ee6d11048e1f74cd5180bad58b9848b4"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/b903e9b5629ec8dd6db92174070045bf81ad7060"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/e0665b2a8e90bb08bd205062c75662b502d31797"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/eb51a9ad3ceb01bc6c0fb608dbc856e03ee6f24a"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H",
      "type": "CVSS_V3"
    }
  ]
}


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