GHSA-9MPH-4HQC-XQX7
Vulnerability from github – Published: 2026-06-25 09:31 – Updated: 2026-09-08 09:35In 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.
{
"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": "2026-09-08T09:35:33Z",
"published": "2026-06-25T09:31:21Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-53223"
},
{
"type": "WEB",
"url": "https://cert-portal.siemens.com/productcert/html/ssa-019113.html"
},
{
"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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