{
  "affected": [
    {
      "ecosystem_specific": {
        "urgency": "not yet assigned"
      },
      "package": {
        "ecosystem": "Debian:12",
        "name": "linux"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "6.1.187-1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "ecosystem_specific": {
        "urgency": "not yet assigned"
      },
      "package": {
        "ecosystem": "Debian:13",
        "name": "linux"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "6.12.105-1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "ecosystem_specific": {
        "urgency": "not yet assigned"
      },
      "package": {
        "ecosystem": "Debian:14",
        "name": "linux"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "7.1.9-1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "ecosystem_specific": {
        "urgency": "not yet assigned"
      },
      "package": {
        "ecosystem": "Debian:12",
        "name": "linux-6.12"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "6.12.107-1~deb12u1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "details": "In the Linux kernel, the following vulnerability has been resolved:  sctp: clear new_transport when removing a peer  sctp_process_asconf_param() stores a newly added peer transport in asoc-\u003enew_transport. After all parameters in the ASCONF chunk have been processed, sctp_sf_do_asconf() uses this pointer to send a HEARTBEAT to the new transport.  An authenticated ASCONF from a remote SCTP peer can add a transport and remove it again with a wildcard DEL-IP parameter in the same chunk. The wildcard deletion preserves the transport on which the ASCONF arrived, but removes the newly added transport through sctp_assoc_del_nonprimary_peers(). The removal does not clear asoc-\u003enew_transport, leaving it pointing to the removed transport.  sctp_sf_do_asconf() then creates a HEARTBEAT whose chunk-\u003etransport points to the removed transport without holding a transport reference. During local address replacement, src_out_of_asoc_ok keeps this HEARTBEAT on control_chunk_list. After the transport is freed by RCU, a successful ASCONF_ACK for the replacement address releases the queued HEARTBEAT and sctp_outq_select_transport() reads the freed transport's state.  The issue was found during a static audit of SCTP objects. With an authenticated peer, the reproducer triggered the same KASAN report in 2 of 2 unpatched runs on a KASAN-enabled netdev/main kernel:    BUG: KASAN: slab-use-after-free in sctp_outq_select_transport   Read of size 4 at addr ffff88800b9bd95c by task python3/197    Call Trace:    sctp_outq_select_transport+0x549/0x8b0 [sctp]    sctp_outq_flush+0x306/0x2c60 [sctp]    sctp_transport_immediate_rtx+0xaf/0x260 [sctp]    sctp_process_asconf_ack+0xa48/0xf70 [sctp]    Allocated by task 197:    sctp_transport_new+0x68/0x650 [sctp]    sctp_assoc_add_peer+0x258/0x12a0 [sctp]    sctp_process_asconf+0x5e9/0x1090 [sctp]    Last potentially related work creation:    __call_rcu_common.constprop.0+0x77/0xb70    sctp_assoc_del_nonprimary_peers+0x7c/0xd0 [sctp]    sctp_process_asconf+0xd9c/0x1090 [sctp]  The first invalid access was a four-byte read of transport-\u003estate at net/sctp/outqueue.c:833. The same reproducer completed the full authenticated ASCONF and local-address replacement sequence with this change without a KASAN report or oops.  Clear new_transport when its peer is removed, before it can be used to create the HEARTBEAT.",
  "id": "DEBIAN-CVE-2026-74586",
  "modified": "2026-09-19T21:47:31.629903563Z",
  "published": "2026-08-22T16:16:30.687Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://security-tracker.debian.org/tracker/CVE-2026-74586"
    }
  ],
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "upstream": [
    "CVE-2026-74586"
  ]
}