{
  "affected": [
    {
      "ecosystem_specific": {
        "urgency": "not yet assigned"
      },
      "package": {
        "ecosystem": "Debian:12",
        "name": "linux"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "ecosystem_specific": {
        "urgency": "not yet assigned"
      },
      "package": {
        "ecosystem": "Debian:13",
        "name": "linux"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "ecosystem_specific": {
        "urgency": "not yet assigned"
      },
      "package": {
        "ecosystem": "Debian:14",
        "name": "linux"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "7.1.5-1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "details": "In the Linux kernel, the following vulnerability has been resolved:  tipc: fix UAF in cleanup_bearer() due to premature dst_cache_destroy()  TIPC UDP media bearer teardown calls dst_cache_destroy() on its replicast caches before calling synchronize_net() to wait for concurrent RCU readers (transmitters) to finish:  static void cleanup_bearer(struct work_struct *work) { ... \tlist_for_each_entry_safe(rcast, tmp, \u0026ub-\u003ercast.list, list) { \t\tdst_cache_destroy(\u0026rcast-\u003edst_cache); \t\tlist_del_rcu(\u0026rcast-\u003elist); \t\tkfree_rcu(rcast, rcu); \t} ... \tdst_cache_destroy(\u0026ub-\u003ercast.dst_cache); \tudp_tunnel_sock_release(ub-\u003esk); \tsynchronize_net(); ... }  This is highly buggy because dst_cache_destroy() immediately frees the per-CPU cache memory (free_percpu()) and releases the cached dst entries without any synchronization.  If a concurrent transmitter (e.g., tipc_udp_xmit()) is running on another CPU under RCU protection, it can call dst_cache_get() concurrently, leading to: 1. Use-After-Free on the per-CPU cache pointer itself (crash). 2. \"rcuref - imbalanced put()\" warning if it attempts to release a    dst that was concurrently released by dst_cache_destroy().  Furthermore, calling kfree(ub) immediately after synchronize_net() without closing the socket first (or waiting after closing it) leaves a window where a concurrent receiver (tipc_udp_recv()) could start after synchronize_net(), access ub, and suffer a UAF when kfree(ub) runs.  To fix this, we must defer dst_cache_destroy() and kfree(ub) until after we have ensured that no more readers can see the bearer/socket and all existing readers have finished:  1. Defer rcast entry destruction (both dst_cache_destroy() and kfree())    to an RCU callback using call_rcu_hurry().    Using call_rcu_hurry() ensures the dst entries are released quickly.  2. Release the bearer socket using udp_tunnel_sock_release() (stops    new receive readers).  3. Call synchronize_net() to wait for all outstanding RCU readers    (both transmit and receive) to finish.  4. Now that it is safe, call dst_cache_destroy() on the main bearer    cache, and free ub.  Note: 3) and 4) can be changed later in net-next to also use call_rcu_hurry() and get rid of the synchronize_net() latency.",
  "id": "DEBIAN-CVE-2026-72404",
  "modified": "2026-09-14T16:47:32.256340605Z",
  "published": "2026-08-15T06:22:13.970Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://security-tracker.debian.org/tracker/CVE-2026-72404"
    }
  ],
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "upstream": [
    "CVE-2026-72404"
  ]
}