{
  "affected": [
    {
      "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:  net/sched: sch_dualpi2: Do not call qdisc_tree_reduce_backlog during peek before restoring qlen  Whenever dualpi2 drops packets during peek, it calls qdisc_tree_reduce_backlog. An issue arises because it calls qdisc_tree_reduce_backlog before it reincrements the qlen. If qlen drops to zero, but peek returns an skb, the parent's qlen_notify callback will be executed even though dualpi2 still has 1 packet on the queue and, thus, mistakenly deactivates the parent's class which leads to a null-ptr-deref:  [  101.427314][  T599] Oops: general protection fault, probably for non-canonical address 0xdffffc0000000009: 0000 [#1] SMP KASAN NOPTI [  101.427755][  T599] KASAN: null-ptr-deref in range [0x0000000000000048-0x000000000000004f] [  101.428048][  T599] CPU: 2 UID: 0 PID: 599 Comm: ping Not tainted 7.1.0-rc5-00284-gbce53c430ed7 #102 PREEMPT(full) [  101.428400][  T599] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 [  101.428608][  T599] RIP: 0010:qfq_dequeue (net/sched/sch_qfq.c:1150) sch_qfq [  101.428821][  T599] Code: 00 fc ff df 80 3c 02 00 0f 85 46 0c 00 00 4c 8d 73 48 48 89 9d b8 02 00 00 48 b8 00 00 00 00 00 fc ff df 4c 89 f2 48 c1 ea 03 \u003c80\u003e 3c 02 00 0f 85 2d 0c 00 00 48 b8 00 00 00 00 00 fc ff df 4c 8b All code [  101.429348][  T599] RSP: 0018:ffff8881110df4f0 EFLAGS: 00010216 [  101.429541][  T599] RAX: dffffc0000000000 RBX: 0000000000000000 RCX: dffffc0000000000 [  101.429763][  T599] RDX: 0000000000000009 RSI: 00000024c0000000 RDI: ffff88811436c2b0 [  101.429985][  T599] RBP: ffff88811436c000 R08: ffff88811436c280 R09: 1ffff11021277523 [  101.430206][  T599] R10: 1ffff11021277526 R11: 1ffff11021277527 R12: 00000024c0000000 [  101.430423][  T599] R13: ffff88811436c2b8 R14: 0000000000000048 R15: 0000000020000000 [  101.430642][  T599] FS:  00007f61813e1c40(0000) GS:ffff8881691ef000(0000) knlGS:0000000000000000 [  101.430913][  T599] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [  101.431100][  T599] CR2: 00005651650850a8 CR3: 000000010ca0b000 CR4: 0000000000750ef0 [  101.431320][  T599] PKRU: 55555554 [  101.431433][  T599] Call Trace: [  101.431544][  T599]  \u003cTASK\u003e [  101.431628][  T599]  __qdisc_run (net/sched/sch_generic.c:322 net/sched/sch_generic.c:427 net/sched/sch_generic.c:445) [  101.431792][  T599]  ? dev_qdisc_enqueue (./include/trace/events/qdisc.h:49 (discriminator 22) net/core/dev.c:4176 (discriminator 22)) [  101.431941][  T599]  __dev_queue_xmit (./include/net/pkt_sched.h:120 ./include/net/pkt_sched.h:117 net/core/dev.c:4292 net/core/dev.c:4831)  Fix this by only calling qdisc_tree_reduce_backlog in peek after the qlen is restored.",
  "id": "DEBIAN-CVE-2026-74266",
  "modified": "2026-09-14T16:47:33.876569056Z",
  "published": "2026-08-15T06:22:25.920Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://security-tracker.debian.org/tracker/CVE-2026-74266"
    }
  ],
  "upstream": [
    "CVE-2026-74266"
  ]
}