{"api_version":"1","generated_at":"2026-08-21T20:40:44+00:00","cve":"CVE-2026-74266","urls":{"html":"https://cve.report/CVE-2026-74266","api":"https://cve.report/api/cve/CVE-2026-74266.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-74266","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-74266"},"summary":{"title":"net/sched: sch_dualpi2: Do not call qdisc_tree_reduce_backlog during peek before restoring qlen","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: sch_dualpi2: Do not call qdisc_tree_reduce_backlog during peek before restoring qlen\n\nWhenever dualpi2 drops packets during peek, it calls\nqdisc_tree_reduce_backlog. An issue arises because it calls\nqdisc_tree_reduce_backlog before it reincrements the qlen. If qlen drops\nto zero, but peek returns an skb, the parent's qlen_notify callback will be\nexecuted even though dualpi2 still has 1 packet on the queue and, thus,\nmistakenly deactivates the parent's class which leads to a null-ptr-deref:\n\n[  101.427314][  T599] Oops: general protection fault, probably for non-canonical address 0xdffffc0000000009: 0000 [#1] SMP KASAN NOPTI\n[  101.427755][  T599] KASAN: null-ptr-deref in range [0x0000000000000048-0x000000000000004f]\n[  101.428048][  T599] CPU: 2 UID: 0 PID: 599 Comm: ping Not tainted 7.1.0-rc5-00284-gbce53c430ed7 #102 PREEMPT(full)\n[  101.428400][  T599] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011\n[  101.428608][  T599] RIP: 0010:qfq_dequeue (net/sched/sch_qfq.c:1150) sch_qfq\n[  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 <80> 3c 02 00 0f 85 2d 0c 00 00 48 b8 00 00 00 00 00 fc ff df 4c 8b\nAll code\n[  101.429348][  T599] RSP: 0018:ffff8881110df4f0 EFLAGS: 00010216\n[  101.429541][  T599] RAX: dffffc0000000000 RBX: 0000000000000000 RCX: dffffc0000000000\n[  101.429763][  T599] RDX: 0000000000000009 RSI: 00000024c0000000 RDI: ffff88811436c2b0\n[  101.429985][  T599] RBP: ffff88811436c000 R08: ffff88811436c280 R09: 1ffff11021277523\n[  101.430206][  T599] R10: 1ffff11021277526 R11: 1ffff11021277527 R12: 00000024c0000000\n[  101.430423][  T599] R13: ffff88811436c2b8 R14: 0000000000000048 R15: 0000000020000000\n[  101.430642][  T599] FS:  00007f61813e1c40(0000) GS:ffff8881691ef000(0000) knlGS:0000000000000000\n[  101.430913][  T599] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n[  101.431100][  T599] CR2: 00005651650850a8 CR3: 000000010ca0b000 CR4: 0000000000750ef0\n[  101.431320][  T599] PKRU: 55555554\n[  101.431433][  T599] Call Trace:\n[  101.431544][  T599]  <TASK>\n[  101.431628][  T599]  __qdisc_run (net/sched/sch_generic.c:322 net/sched/sch_generic.c:427 net/sched/sch_generic.c:445)\n[  101.431792][  T599]  ? dev_qdisc_enqueue (./include/trace/events/qdisc.h:49 (discriminator 22) net/core/dev.c:4176 (discriminator 22))\n[  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)\n\nFix this by only calling qdisc_tree_reduce_backlog in peek after the\nqlen is restored.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-08-15 06:22:25","updated_at":"2026-08-17 06:19:20"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/bd851b10daee7199a658458b8ce250e95a334500","name":"https://git.kernel.org/stable/c/bd851b10daee7199a658458b8ce250e95a334500","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/466f29477cae2bd1982a066d518a9b20c5a37924","name":"https://git.kernel.org/stable/c/466f29477cae2bd1982a066d518a9b20c5a37924","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/15cd0c93bf4f892d66bc7a93667e2357b5673365","name":"https://git.kernel.org/stable/c/15cd0c93bf4f892d66bc7a93667e2357b5673365","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-74266","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-74266","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 8f9516daedd67097a0c6e463fcb7a42b5ee9d477 bd851b10daee7199a658458b8ce250e95a334500 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 8f9516daedd67097a0c6e463fcb7a42b5ee9d477 466f29477cae2bd1982a066d518a9b20c5a37924 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 8f9516daedd67097a0c6e463fcb7a42b5ee9d477 15cd0c93bf4f892d66bc7a93667e2357b5673365 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.17","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.17 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.40 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.1.5 7.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"74266","cve":"CVE-2026-74266","epss":"0.001980000","percentile":"0.099080000","score_date":"2026-08-17","updated_at":"2026-08-18 00:11:46"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["net/sched/sch_dualpi2.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"bd851b10daee7199a658458b8ce250e95a334500","status":"affected","version":"8f9516daedd67097a0c6e463fcb7a42b5ee9d477","versionType":"git"},{"lessThan":"466f29477cae2bd1982a066d518a9b20c5a37924","status":"affected","version":"8f9516daedd67097a0c6e463fcb7a42b5ee9d477","versionType":"git"},{"lessThan":"15cd0c93bf4f892d66bc7a93667e2357b5673365","status":"affected","version":"8f9516daedd67097a0c6e463fcb7a42b5ee9d477","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["net/sched/sch_dualpi2.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"6.17"},{"lessThan":"6.17","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.40","versionType":"semver"},{"lessThanOrEqual":"7.1.*","status":"unaffected","version":"7.1.5","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.2","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.40","versionStartIncluding":"6.17","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.1.5","versionStartIncluding":"6.17","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2","versionStartIncluding":"6.17","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: sch_dualpi2: Do not call qdisc_tree_reduce_backlog during peek before restoring qlen\n\nWhenever dualpi2 drops packets during peek, it calls\nqdisc_tree_reduce_backlog. An issue arises because it calls\nqdisc_tree_reduce_backlog before it reincrements the qlen. If qlen drops\nto zero, but peek returns an skb, the parent's qlen_notify callback will be\nexecuted even though dualpi2 still has 1 packet on the queue and, thus,\nmistakenly deactivates the parent's class which leads to a null-ptr-deref:\n\n[  101.427314][  T599] Oops: general protection fault, probably for non-canonical address 0xdffffc0000000009: 0000 [#1] SMP KASAN NOPTI\n[  101.427755][  T599] KASAN: null-ptr-deref in range [0x0000000000000048-0x000000000000004f]\n[  101.428048][  T599] CPU: 2 UID: 0 PID: 599 Comm: ping Not tainted 7.1.0-rc5-00284-gbce53c430ed7 #102 PREEMPT(full)\n[  101.428400][  T599] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011\n[  101.428608][  T599] RIP: 0010:qfq_dequeue (net/sched/sch_qfq.c:1150) sch_qfq\n[  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 <80> 3c 02 00 0f 85 2d 0c 00 00 48 b8 00 00 00 00 00 fc ff df 4c 8b\nAll code\n[  101.429348][  T599] RSP: 0018:ffff8881110df4f0 EFLAGS: 00010216\n[  101.429541][  T599] RAX: dffffc0000000000 RBX: 0000000000000000 RCX: dffffc0000000000\n[  101.429763][  T599] RDX: 0000000000000009 RSI: 00000024c0000000 RDI: ffff88811436c2b0\n[  101.429985][  T599] RBP: ffff88811436c000 R08: ffff88811436c280 R09: 1ffff11021277523\n[  101.430206][  T599] R10: 1ffff11021277526 R11: 1ffff11021277527 R12: 00000024c0000000\n[  101.430423][  T599] R13: ffff88811436c2b8 R14: 0000000000000048 R15: 0000000020000000\n[  101.430642][  T599] FS:  00007f61813e1c40(0000) GS:ffff8881691ef000(0000) knlGS:0000000000000000\n[  101.430913][  T599] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n[  101.431100][  T599] CR2: 00005651650850a8 CR3: 000000010ca0b000 CR4: 0000000000750ef0\n[  101.431320][  T599] PKRU: 55555554\n[  101.431433][  T599] Call Trace:\n[  101.431544][  T599]  <TASK>\n[  101.431628][  T599]  __qdisc_run (net/sched/sch_generic.c:322 net/sched/sch_generic.c:427 net/sched/sch_generic.c:445)\n[  101.431792][  T599]  ? dev_qdisc_enqueue (./include/trace/events/qdisc.h:49 (discriminator 22) net/core/dev.c:4176 (discriminator 22))\n[  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)\n\nFix this by only calling qdisc_tree_reduce_backlog in peek after the\nqlen is restored."}],"providerMetadata":{"dateUpdated":"2026-08-17T05:16:08.881Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/bd851b10daee7199a658458b8ce250e95a334500"},{"url":"https://git.kernel.org/stable/c/466f29477cae2bd1982a066d518a9b20c5a37924"},{"url":"https://git.kernel.org/stable/c/15cd0c93bf4f892d66bc7a93667e2357b5673365"}],"title":"net/sched: sch_dualpi2: Do not call qdisc_tree_reduce_backlog during peek before restoring qlen","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-74266","datePublished":"2026-08-15T05:57:41.611Z","dateReserved":"2026-08-15T05:44:03.878Z","dateUpdated":"2026-08-17T05:16:08.881Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-08-15 06:22:25","lastModifiedDate":"2026-08-17 06:19:20","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"74266","Ordinal":"1","Title":"net/sched: sch_dualpi2: Do not call qdisc_tree_reduce_backlog du","CVE":"CVE-2026-74266","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"74266","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: sch_dualpi2: Do not call qdisc_tree_reduce_backlog during peek before restoring qlen\n\nWhenever dualpi2 drops packets during peek, it calls\nqdisc_tree_reduce_backlog. An issue arises because it calls\nqdisc_tree_reduce_backlog before it reincrements the qlen. If qlen drops\nto zero, but peek returns an skb, the parent's qlen_notify callback will be\nexecuted even though dualpi2 still has 1 packet on the queue and, thus,\nmistakenly deactivates the parent's class which leads to a null-ptr-deref:\n\n[  101.427314][  T599] Oops: general protection fault, probably for non-canonical address 0xdffffc0000000009: 0000 [#1] SMP KASAN NOPTI\n[  101.427755][  T599] KASAN: null-ptr-deref in range [0x0000000000000048-0x000000000000004f]\n[  101.428048][  T599] CPU: 2 UID: 0 PID: 599 Comm: ping Not tainted 7.1.0-rc5-00284-gbce53c430ed7 #102 PREEMPT(full)\n[  101.428400][  T599] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011\n[  101.428608][  T599] RIP: 0010:qfq_dequeue (net/sched/sch_qfq.c:1150) sch_qfq\n[  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 <80> 3c 02 00 0f 85 2d 0c 00 00 48 b8 00 00 00 00 00 fc ff df 4c 8b\nAll code\n[  101.429348][  T599] RSP: 0018:ffff8881110df4f0 EFLAGS: 00010216\n[  101.429541][  T599] RAX: dffffc0000000000 RBX: 0000000000000000 RCX: dffffc0000000000\n[  101.429763][  T599] RDX: 0000000000000009 RSI: 00000024c0000000 RDI: ffff88811436c2b0\n[  101.429985][  T599] RBP: ffff88811436c000 R08: ffff88811436c280 R09: 1ffff11021277523\n[  101.430206][  T599] R10: 1ffff11021277526 R11: 1ffff11021277527 R12: 00000024c0000000\n[  101.430423][  T599] R13: ffff88811436c2b8 R14: 0000000000000048 R15: 0000000020000000\n[  101.430642][  T599] FS:  00007f61813e1c40(0000) GS:ffff8881691ef000(0000) knlGS:0000000000000000\n[  101.430913][  T599] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n[  101.431100][  T599] CR2: 00005651650850a8 CR3: 000000010ca0b000 CR4: 0000000000750ef0\n[  101.431320][  T599] PKRU: 55555554\n[  101.431433][  T599] Call Trace:\n[  101.431544][  T599]  <TASK>\n[  101.431628][  T599]  __qdisc_run (net/sched/sch_generic.c:322 net/sched/sch_generic.c:427 net/sched/sch_generic.c:445)\n[  101.431792][  T599]  ? dev_qdisc_enqueue (./include/trace/events/qdisc.h:49 (discriminator 22) net/core/dev.c:4176 (discriminator 22))\n[  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)\n\nFix this by only calling qdisc_tree_reduce_backlog in peek after the\nqlen is restored.","Type":"Description","Title":"net/sched: sch_dualpi2: Do not call qdisc_tree_reduce_backlog du"}]}}}