{"id":7200,"date":"2026-09-04T18:49:28","date_gmt":"2026-09-04T10:49:28","guid":{"rendered":"https:\/\/www.54iter.cn\/?vuln=cve-2026-74267"},"modified":"2026-09-04T18:49:28","modified_gmt":"2026-09-04T10:49:28","slug":"cve-2026-74267","status":"publish","type":"vuln","link":"https:\/\/www.54iter.cn\/?vuln=cve-2026-74267","title":{"rendered":"CVE-2026-74267 [CRITICAL] &#8211; In the Linux kernel, the following vulnerability has been resolved:\n\nnet\/sched: sch_codel:"},"content":{"rendered":"<p>In the Linux kernel, the following vulnerability has been resolved:<\/p>\n<p>net\/sched: sch_codel: Do not call qdisc_tree_reduce_backlog during peek before restoring qlen<\/p>\n<p>Whenever codel drops packets during peek, it calls<br \/>\nqdisc_tree_reduce_backlog. An issue arises because it calls<br \/>\nqdisc_tree_reduce_backlog before it reincrements the qlen. If qlen drops<br \/>\nto zero, but peek returns an skb, the parent&#8217;s qlen_notify callback will<br \/>\nbe executed even though codel still has 1 packet on the queue and, thus,<br \/>\nwill mistakenly deactivate the parent&#8217;s class causing issues like a wild<br \/>\nmemory access when qfq has codel as a child:<\/p>\n<p>[   36.339843][  T370] Oops: general protection fault, probably for non-canonical address 0xfbd59c0000000024: 0000 [#1] SMP KASAN NOPTI<br \/>\n[   36.340408][  T370] KASAN: maybe wild-memory-access in range [0xdead000000000120-0xdead000000000127]<br \/>\n[   36.340737][  T370] CPU: 2 UID: 0 PID: 370 Comm: tc Not tainted 7.1.0-rc5-00287-g66e13b626592 #87 PREEMPT(full)<br \/>\n[   36.341113][  T370] Hardware name: Bochs Bochs, BIOS Bochs 01\/01\/2011<br \/>\n[   36.341357][  T370] RIP: 0010:qfq_deactivate_agg (include\/linux\/list.h:1029 (discriminator 2) include\/linux\/list.h:1043 (discriminator 2) net\/sched\/sch_qfq.c:1369 (discriminator 2) net\/sched\/sch_qfq.c:1395 (discriminator 2)) sch_qfq<br \/>\n[   36.342221][  T370] RSP: 0018:ffff8881100ef370 EFLAGS: 00010216<br \/>\n[   36.342422][  T370] RAX: 0000000000000000 RBX: ffff8881058a9568 RCX: dffffc0000000000<br \/>\n[   36.342664][  T370] RDX: 1ffff11021064dc3 RSI: ffff888108326e00 RDI: dffffc0000000000<br \/>\n[   36.342905][  T370] RBP: ffff8881058a8280 R08: dead000000000122 R09: 1bd5a00000000024<br \/>\n[   36.343140][  T370] R10: fffffbfff2940329 R11: fffffbfff2940329 R12: 0000000000000000<br \/>\n[   36.343383][  T370] R13: dead000000000100 R14: ffff8881058a9580 R15: ffff8881058a9578<br \/>\n[   36.343631][  T370] FS:  00007fc04b0ca780(0000) GS:ffff888184fef000(0000) knlGS:0000000000000000<br \/>\n[   36.343911][  T370] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033<br \/>\n[   36.344116][  T370] CR2: 0000557c02c02000 CR3: 000000010e0ba000 CR4: 0000000000750ef0<br \/>\n[   36.344359][  T370] PKRU: 55555554<br \/>\n[   36.344481][  T370] Call Trace:<br \/>\n&#8230;<br \/>\n[   36.345054][  T370] qfq_reset_qdisc (net\/sched\/sch_qfq.c:357 net\/sched\/sch_qfq.c:1487) sch_qfq<br \/>\n[   36.345222][  T370]  qdisc_reset (net\/sched\/sch_generic.c:1057)<br \/>\n[   36.345503][  T370]  __qdisc_destroy (net\/sched\/sch_generic.c:1096)<br \/>\n[   36.345677][  T370]  qdisc_graft (net\/sched\/sch_api.c:1062 net\/sched\/sch_api.c:1053 net\/sched\/sch_api.c:1159)<br \/>\n[   36.346335][  T370]  tc_get_qdisc (net\/sched\/sch_api.c:1528 net\/sched\/sch_api.c:1556)<\/p>\n<p>Fix this by only calling qdisc_tree_reduce_backlog in peek after the<br \/>\nqlen is restored.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>In the Linux kernel, the following vulnerability has been resolved:<\/p>\n<p>net\/sched: sch_codel: Do not call qdisc_tree_reduce_backlog during peek before restoring qlen<\/p>\n<p>Whenever codel drops packets during <\/p>\n","protected":false},"template":"","meta":[],"categories":[],"tags":[],"class_list":["post-7200","vuln","type-vuln","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln\/7200","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln"}],"about":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/types\/vuln"}],"wp:attachment":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=7200"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=7200"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=7200"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}