{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2"
            },
            {
              "fixed": "f60ec3058a85447008b88b762c859d336163acb3"
            },
            {
              "fixed": "95128dc74425ec19ed4f2077ccc651e791ff4b75"
            },
            {
              "fixed": "3546deaa0c30a14c7cdb5dc8f2432cb428f0cd36"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "2.6.12"
            },
            {
              "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/2026/72xxx/CVE-2026-72321.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nipv4: igmp: Fix potential memory leaks in igmp_mod_timer() and igmp_stop_timer()\n\nWhen a timer is deleted and not re-armed in igmp_mod_timer(), or stopped\nin igmp_stop_timer(), the code currently decrements the reference counter\nof the multicast list entry @im using refcount_dec(\u0026im-\u003erefcnt).\n\nHowever, both functions can be called from the RCU reader path:\n- igmp_mod_timer() via igmp_heard_query() -\u003e for_each_pmc_rcu()\n- igmp_stop_timer() via igmp_rcv() -\u003e igmp_heard_report()\n\nIf the group im was concurrently removed from the list by ip_mc_dec_group(),\nits reference count might have already been decremented to 1.\n\nIn this case, timer_delete() succeeds, and refcount_dec() decrements\nthe refcount from 1 to 0. Since refcount_dec() does not free the object\nwhen it hits 0 (unlike ip_ma_put()), the im structure is leaked.\n\nFix this by using ip_ma_put(im) instead of refcount_dec(\u0026im-\u003erefcnt),\nand deferring the put until after the spinlock is released.",
  "id": "CVE-2026-72321",
  "modified": "2026-08-16T03:31:08.745888068Z",
  "published": "2026-08-15T05:55:33.547Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/3546deaa0c30a14c7cdb5dc8f2432cb428f0cd36"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/95128dc74425ec19ed4f2077ccc651e791ff4b75"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/f60ec3058a85447008b88b762c859d336163acb3"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/72xxx/CVE-2026-72321.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-72321"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.9.0",
  "summary": "ipv4: igmp: Fix potential memory leaks in igmp_mod_timer() and igmp_stop_timer()"
}