{"id":"DEBIAN-CVE-2026-74266","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.","modified":"2026-09-14T16:47:33.876569056Z","published":"2026-08-15T06:22:25.920Z","upstream":["CVE-2026-74266"],"references":[{"type":"ADVISORY","url":"https://security-tracker.debian.org/tracker/CVE-2026-74266"}],"affected":[{"package":{"name":"linux","ecosystem":"Debian:14","purl":"pkg:deb/debian/linux?arch=source&distro=forky"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"7.1.5-1"}]}],"versions":["6.12.100-1","6.12.101-1","6.12.105-1","6.12.107-1","6.12.38-1","6.12.41-1","6.12.43-1","6.12.43-1~bpo12+1","6.12.48-1","6.12.57-1","6.12.57-1~bpo12+1","6.12.63-1","6.12.63-1~bpo12+1","6.12.69-1","6.12.69-1~bpo12+1","6.12.73-1","6.12.73-1~bpo12+1","6.12.74-1","6.12.74-2","6.12.74-2~bpo12+1","6.12.85-1","6.12.85-1~bpo12+1","6.12.86-1","6.12.86-1~bpo12+1","6.12.88-1","6.12.88-1~bpo12+1","6.12.90-1","6.12.90-1~bpo12+1","6.12.90-2","6.12.90-2~bpo12+1","6.12.94-1","6.12.94-1~bpo12+1","6.12.95-1","6.12.95-1~bpo12+1","6.12.96-1","6.13.10-1~exp1","6.13.11-1~exp1","6.13.2-1~exp1","6.13.3-1~exp1","6.13.4-1~exp1","6.13.5-1~exp1","6.13.6-1~exp1","6.13.7-1~exp1","6.13.8-1~exp1","6.13.9-1~exp1","6.13~rc6-1~exp1","6.13~rc7-1~exp1","6.14.3-1~exp1","6.14.5-1~exp1","6.14.6-1~exp1","6.15-1~exp1","6.15.1-1~exp1","6.15.2-1~exp1","6.15.3-1~exp1","6.15.4-1~exp1","6.15.5-1~exp1","6.15.6-1~exp1","6.15~rc7-1~exp1","6.16-1~exp1","6.16.1-1~exp1","6.16.10-1","6.16.11-1","6.16.12-1","6.16.12-1~bpo13+1","6.16.12-2","6.16.3-1","6.16.3-1~bpo13+1","6.16.5-1","6.16.6-1","6.16.7-1","6.16.8-1","6.16.9-1","6.16~rc7-1~exp1","6.17.10-1","6.17.11-1","6.17.12-1","6.17.13-1","6.17.13-1~bpo13+1","6.17.2-1~exp1","6.17.5-1~exp1","6.17.6-1","6.17.7-1","6.17.7-2","6.17.8-1","6.17.8-1~bpo13+1","6.17.9-1","6.18.1-1~exp1","6.18.10-1","6.18.12-1","6.18.12-1~bpo13+1","6.18.13-1","6.18.14-1","6.18.15-1","6.18.15-1~bpo13+1","6.18.2-1~exp1","6.18.3-1","6.18.5-1","6.18.5-1~bpo13+1","6.18.8-1","6.18.9-1","6.18.9-1~bpo13+1","6.18~rc4-1~exp1","6.18~rc4-1~exp2","6.18~rc5-1~exp1","6.18~rc6-1~exp1","6.18~rc7-1~exp1","6.19-1~exp1","6.19.10-1","6.19.10-1~bpo13+1","6.19.11-1","6.19.11-1~bpo13+1","6.19.12-1","6.19.13-1","6.19.13-1~bpo13+1","6.19.14-1","6.19.14-1~bpo13+1","6.19.2-1~exp1","6.19.3-1~exp1","6.19.4-1~exp1","6.19.5-1~exp1","6.19.6-1","6.19.6-2","6.19.6-2~bpo13+1","6.19.8-1","6.19.8-1~bpo13+1","6.19~rc4-1~exp1","6.19~rc5-1~exp1","6.19~rc6-1~exp1","6.19~rc7-1~exp1","6.19~rc8-1~exp1","7.0-1~exp1","7.0.1-1~exp1","7.0.10-1","7.0.10-1~bpo13+1","7.0.12-1","7.0.12-2","7.0.12-2~bpo13+1","7.0.13-1","7.0.13-1~bpo13+1","7.0.14-1","7.0.3-1","7.0.4-1","7.0.4-1~bpo13+1","7.0.7-1","7.0.7-1~bpo13+1","7.0.9-1","7.0.9-1~bpo13+1","7.1.1-1~exp1","7.1.2-1~exp1","7.1.3-1","7.1.3-1+sunvdc","7.1.3-1~bpo13+1","7.1.4-1","7.1~rc2-1~exp1","7.1~rc3-1~exp1","7.1~rc4-1~exp1","7.1~rc4-1~exp2","7.1~rc5-1~exp1","7.1~rc7-1~exp1"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-74266.json"}}],"schema_version":"1.9.0"}