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GHSA-GVV5-3H67-3922

Vulnerability from github – Published: 2026-09-04 18:31 – Updated: 2026-09-04 18:31
VLAI
Details

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

xfrm: espintcp: fix UAF during close

ZDI reported and analyzed a race condition during close for espintcp sockets:

espintcp_close() frees emsg->skb via kfree_skb() without holding
any socket lock. Concurrently, the xfrm_trans_reinject work queue
invokes esp_output_tcp_finish() -> espintcp_push_skb() ->
espintcp_push_msgs() -> skb_send_sock_locked(), which reads the
same skb as a data source.

Fix this by adding a synchronize_rcu() call after resetting sk_prot, since esp_output_tcp_finish() runs under RCU and won't use a socket with sk_prot == &tcp_prot. Simply taking the socket lock in espintcp_close() could lead to leaks, if esp_output_tcp_finish() re-adds an skb in the slot we just freed. After this, the existing barrier() is no longer needed.

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{
  "affected": [],
  "aliases": [
    "CVE-2026-80848"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-09-04T16:18:13Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nxfrm: espintcp: fix UAF during close\n\nZDI reported and analyzed a race condition during close for espintcp\nsockets:\n\n    espintcp_close() frees emsg-\u003eskb via kfree_skb() without holding\n    any socket lock. Concurrently, the xfrm_trans_reinject work queue\n    invokes esp_output_tcp_finish() -\u003e espintcp_push_skb() -\u003e\n    espintcp_push_msgs() -\u003e skb_send_sock_locked(), which reads the\n    same skb as a data source.\n\nFix this by adding a synchronize_rcu() call after resetting sk_prot,\nsince esp_output_tcp_finish() runs under RCU and won\u0027t use a socket\nwith sk_prot == \u0026tcp_prot.  Simply taking the socket lock in\nespintcp_close() could lead to leaks, if esp_output_tcp_finish()\nre-adds an skb in the slot we just freed. After this, the existing\nbarrier() is no longer needed.",
  "id": "GHSA-gvv5-3h67-3922",
  "modified": "2026-09-04T18:31:28Z",
  "published": "2026-09-04T18:31:28Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-80848"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/24efebecf415ba264adba0f0491cec436463a14f"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/29121c5e6591da527e8e36ddac7120dc527f574d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/4b31a875693c480c611519faca46216514e3e052"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/4bc0dfa28dca6fc0084203732695968049c44072"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/54b41ad14da9a981131ab6e4d3f79321a503ea5d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/deb232e884877bf10b4ce2580909eedec986c284"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/eb3bbf29c723fe75c0eb92be14f0ec92971fe272"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ed5d9102190c45fc70121c036b0626b740040b75"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ff8dd7a932f34409a56e1b91a1219340f17457e9"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}



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