{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "25b0b9c4e835ffaa65b61c3efe2e28acf84d0259"
            },
            {
              "fixed": "380413cdfd29fb9fa486c82889132b680c4983c5"
            },
            {
              "fixed": "f05b3f4c78370469286879c765f5a1dd39dbcd32"
            },
            {
              "fixed": "4da2ac7749411971e1b222b992da5a172ce45f98"
            },
            {
              "fixed": "5e215bf1c47fdddf8203a0fe80a0ed594065f101"
            },
            {
              "fixed": "ec7d54d8cc1723921d671e3272b427c96366506f"
            },
            {
              "fixed": "a0c5fdeb5fa257f8c6d469af266bc087cb5de6a2"
            },
            {
              "fixed": "b65289e1c3f352a9f92c6e19713ddd647e033253"
            },
            {
              "fixed": "1579342d71133da7f00daa02c75cebec7372097b"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "4.17.0"
            },
            {
              "fixed": "5.10.265"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "5.11.0"
            },
            {
              "fixed": "5.15.216"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "5.16.0"
            },
            {
              "fixed": "6.1.183"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.2.0"
            },
            {
              "fixed": "6.6.145"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.7.0"
            },
            {
              "fixed": "6.12.97"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.13.0"
            },
            {
              "fixed": "6.18.40"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.19.0"
            },
            {
              "fixed": "7.1.5"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64543.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\ntipc: fix use-after-free of the discoverer in tipc_disc_rcv()\n\nbearer_disable() frees b-\u003edisc with tipc_disc_delete()'s plain kfree(),\nbut tipc_disc_rcv() still dereferences b-\u003edisc in RX softirq under\nrcu_read_lock() (tipc_udp_recv -\u003e tipc_rcv -\u003e tipc_disc_rcv).\n\nL2 bearers are safe thanks to the synchronize_net() in\ntipc_disable_l2_media(), but the UDP bearer defers that call to the\ncleanup_bearer() workqueue, so the discoverer is freed with no grace\nperiod:\n\n BUG: KASAN: slab-use-after-free in tipc_disc_rcv (net/tipc/discover.c:149)\n Read of size 8 at addr ffff88802348b728 by task poc_tipc/184\n \u003cIRQ\u003e\n  tipc_disc_rcv (net/tipc/discover.c:149)\n  tipc_rcv (net/tipc/node.c:2126)\n  tipc_udp_recv (net/tipc/udp_media.c:391)\n  udp_rcv (net/ipv4/udp.c:2643)\n  ip_local_deliver_finish (net/ipv4/ip_input.c:241)\n \u003c/IRQ\u003e\n Freed by task 181:\n  kfree (mm/slub.c:6565)\n  bearer_disable (net/tipc/bearer.c:418)\n  tipc_nl_bearer_disable (net/tipc/bearer.c:1001)\n\nThe bearer is freed with kfree_rcu(); free the discoverer the same way.\nAdd an rcu_head to struct tipc_discoverer and free it and its skb from an\nRCU callback.\n\nBecause the RCU callback (tipc_disc_free_rcu) lives in module text, a\ncall_rcu() that is still pending when the tipc module is unloaded would\ninvoke a freed function. Add an rcu_barrier() to tipc_exit() after the\nbearer subsystem has been torn down, so all pending discoverer callbacks\nhave run before the module text goes away.\n\nReachable from an unprivileged user namespace: the TIPCv2 genl family is\nnetnsok and its bearer commands have no GENL_ADMIN_PERM. Needs CONFIG_TIPC\nand CONFIG_TIPC_MEDIA_UDP.",
  "id": "CVE-2026-64543",
  "modified": "2026-08-21T03:30:33.734831855Z",
  "published": "2026-07-27T20:10:35.565Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/1579342d71133da7f00daa02c75cebec7372097b"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/380413cdfd29fb9fa486c82889132b680c4983c5"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/4da2ac7749411971e1b222b992da5a172ce45f98"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/5e215bf1c47fdddf8203a0fe80a0ed594065f101"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/a0c5fdeb5fa257f8c6d469af266bc087cb5de6a2"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/b65289e1c3f352a9f92c6e19713ddd647e033253"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ec7d54d8cc1723921d671e3272b427c96366506f"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/f05b3f4c78370469286879c765f5a1dd39dbcd32"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64543.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-64543"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "tipc: fix use-after-free of the discoverer in tipc_disc_rcv()"
}