{
  "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"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "details": "In the Linux kernel, the following vulnerability has been resolved:  igmp: convert struct ip_sf_list to RCU  Commit 23d2b94043ca (\"igmp: Add ip_mc_list lock in ip_check_mc_rcu\") added spin_lock_bh(\u0026im-\u003elock) to ip_check_mc_rcu() to prevent a use-after-free while iterating im-\u003esources during concurrent deletions.  However, ip_check_mc_rcu() is called from RCU read-side critical sections in packet receive and route lookup fast paths (e.g. __mkroute_output(), ip_route_input_rcu(), and __udp4_lib_rcv()).  When igmpv3_send_cr() or igmpv3_send_report() holds \u0026pmc-\u003elock and calls add_grec() -\u003e igmpv3_newpack() -\u003e ip_route_output_ports(), an XFRM policy matching a multicast destination triggers xfrm_tmpl_resolve_one() -\u003e xfrm4_get_saddr() -\u003e __mkroute_output() -\u003e ip_check_mc_rcu(). This attempts to acquire \u0026im-\u003elock while \u0026pmc-\u003elock is already held on the same CPU, triggering a lockdep recursive locking warning / deadlock.  Fix this by converting IPv4 struct ip_sf_list to RCU, mirroring the IPv6 implementation in net/ipv6/mcast.c:  1. Add struct rcu_head to struct ip_sf_list and annotate sf_next,    sources, and tomb as __rcu pointers. 2. Use rcu_assign_pointer() and kfree_rcu() for list updates and    deletions. 3. Remove spin_lock_bh(\u0026im-\u003elock) from ip_check_mc_rcu() and traverse    im-\u003esources locklessly with for_each_psf_rcu(), reading and writing    counter fields with READ_ONCE() and WRITE_ONCE().  Note: RCU conversion of /proc/net/mcfilter will be done in a separate patch.",
  "id": "DEBIAN-CVE-2026-98103",
  "modified": "2026-09-26T04:47:32.414115047Z",
  "published": "2026-09-25T11:17:40.613Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://security-tracker.debian.org/tracker/CVE-2026-98103"
    }
  ],
  "upstream": [
    "CVE-2026-98103"
  ]
}