HighFix available

net: guard timestamp cmsgs to real error queue skbs

Type: advisorySources: OSV

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.

Products: Kernel
Affected versions: Not specified
Fixed versions: 5.10.259, 5.15.210, 6.1.176, 6.12.94, 6.18.36, 6.6.143, 7.0.13
CVEs: CVE-2026-53223
Confirmed fixed CVEs: Not specified
Updated in this feed: 3 Nov 2026, 03:24 UTC · Revision 1

Source evidence

net: guard timestamp cmsgs to real error queue skbs

core-osv · Original source

Published 25 Jun 2026, 08:39 UTC

osv:CVE-2026-53223

Kernel

Fixed versions: 5.10.259, 5.15.210, 6.1.176, 6.6.143, 6.12.94, 6.18.36, 7.0.13

Complete source record

{
  "id": "08cc4db40d3120b8f5dc241430f1ea53d1dff42c34d2b0a3f720511064a64357",
  "url": "https://osv.dev/vulnerability/CVE-2026-53223",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "net: guard timestamp cmsgs to real error queue skbs",
    "summary": "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.",
    "evidence": "osv:CVE-2026-53223",
    "products": [
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        "name": {
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        "prerequisites": [],
        "fixed_versions": [
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          {
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            "evidence": "/affected/1/ranges"
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                {
                  "introduced": "4.10.14"
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      "modified": "2026-10-28T02:30:25.497441161Z",
      "provider": "osv",
      "references": [
        "https://cert-portal.siemens.com/productcert/html/ssa-019113.html",
        "https://cert-portal.siemens.com/productcert/html/ssa-457936.html",
        "https://git.kernel.org/stable/c/1ee90b77b727df903033db873c75caac5c27ec98",
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        "https://git.kernel.org/stable/c/71ff5cdd5da61d0438e902aa0fd68c28bc901abe",
        "https://git.kernel.org/stable/c/ad9a0374ee6d11048e1f74cd5180bad58b9848b4",
        "https://git.kernel.org/stable/c/b903e9b5629ec8dd6db92174070045bf81ad7060",
        "https://git.kernel.org/stable/c/e0665b2a8e90bb08bd205062c75662b502d31797",
        "https://git.kernel.org/stable/c/eb51a9ad3ceb01bc6c0fb608dbc856e03ee6f24a",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/53xxx/CVE-2026-53223.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-53223",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
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      "provider_metadata": {
        "cna_assigner": "Linux",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/53xxx/CVE-2026-53223.json"
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    "related_cves": [
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    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
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  "source_id": "core-osv",
  "document_id": 492166,
  "published_at": "2026-06-25T08:39:24.588+00:00"
}