{"api_version":"1","generated_at":"2026-10-01T19:17:13+00:00","cve":"CVE-2026-98017","urls":{"html":"https://cve.report/CVE-2026-98017","api":"https://cve.report/api/cve/CVE-2026-98017.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-98017","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-98017"},"summary":{"title":"net/sched: defer qdisc freeing after failed creation","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: defer qdisc freeing after failed creation\n\nAn RTM_NEWQDISC request can make clsact bind a populated shared ingress\nblock during ->init(), publishing an embedded mini_Qdisc to lockless\nreaders.  If the same request has an invalid TCA_RATE, estimator setup\nfails after ->init(); the unwind removes the pointer but synchronously\nfrees its containing qdisc while tc_run() may still hold it.\n\nRetire failed qdiscs through the same RCU helper as normal destruction.\nInline the synchronous free into the callback now that no direct callers\nremain.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-09-25 11:17:30","updated_at":"2026-09-25 15:18:03"},"problem_types":[],"metrics":[{"version":"3.1","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","score":"7.8","severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","data":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7.8,"baseSeverity":"HIGH","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"}},{"version":"3.1","source":"CNA","type":"DECLARED","score":"7.8","severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","data":{"baseScore":7.8,"baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","version":"3.1"}}],"references":[{"url":"https://git.kernel.org/stable/c/20bf6fa34b345333971bd4464a322cce87b83f4e","name":"https://git.kernel.org/stable/c/20bf6fa34b345333971bd4464a322cce87b83f4e","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/e6662f2100f8d33b0f4d0047c219efd6bba186ea","name":"https://git.kernel.org/stable/c/e6662f2100f8d33b0f4d0047c219efd6bba186ea","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/156a3bab69744e9225bb9eff8c5cc53da18d5a2e","name":"https://git.kernel.org/stable/c/156a3bab69744e9225bb9eff8c5cc53da18d5a2e","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/5bfe927c5b4b290fad529186218c728589b4b101","name":"https://git.kernel.org/stable/c/5bfe927c5b4b290fad529186218c728589b4b101","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-98017","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-98017","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 51ab2994c387c80b45caf8b8067b3f3b97771d25 20bf6fa34b345333971bd4464a322cce87b83f4e git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 51ab2994c387c80b45caf8b8067b3f3b97771d25 156a3bab69744e9225bb9eff8c5cc53da18d5a2e git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 51ab2994c387c80b45caf8b8067b3f3b97771d25 5bfe927c5b4b290fad529186218c728589b4b101 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 51ab2994c387c80b45caf8b8067b3f3b97771d25 e6662f2100f8d33b0f4d0047c219efd6bba186ea git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 4.16","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 4.16 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.111 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.53 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2.7 7.2.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.3-rc3 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"98017","cve":"CVE-2026-98017","epss":"0.001280000","percentile":"0.020970000","score_date":"2026-09-27","updated_at":"2026-09-28 00:02:23"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["include/net/sch_generic.h","net/sched/sch_api.c","net/sched/sch_generic.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"20bf6fa34b345333971bd4464a322cce87b83f4e","status":"affected","version":"51ab2994c387c80b45caf8b8067b3f3b97771d25","versionType":"git"},{"lessThan":"156a3bab69744e9225bb9eff8c5cc53da18d5a2e","status":"affected","version":"51ab2994c387c80b45caf8b8067b3f3b97771d25","versionType":"git"},{"lessThan":"5bfe927c5b4b290fad529186218c728589b4b101","status":"affected","version":"51ab2994c387c80b45caf8b8067b3f3b97771d25","versionType":"git"},{"lessThan":"e6662f2100f8d33b0f4d0047c219efd6bba186ea","status":"affected","version":"51ab2994c387c80b45caf8b8067b3f3b97771d25","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["include/net/sch_generic.h","net/sched/sch_api.c","net/sched/sch_generic.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"4.16"},{"lessThan":"4.16","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.111","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.53","versionType":"semver"},{"lessThanOrEqual":"7.2.*","status":"unaffected","version":"7.2.7","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.3-rc3","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.111","versionStartIncluding":"4.16","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.53","versionStartIncluding":"4.16","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2.7","versionStartIncluding":"4.16","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.3-rc3","versionStartIncluding":"4.16","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: defer qdisc freeing after failed creation\n\nAn RTM_NEWQDISC request can make clsact bind a populated shared ingress\nblock during ->init(), publishing an embedded mini_Qdisc to lockless\nreaders.  If the same request has an invalid TCA_RATE, estimator setup\nfails after ->init(); the unwind removes the pointer but synchronously\nfrees its containing qdisc while tc_run() may still hold it.\n\nRetire failed qdiscs through the same RCU helper as normal destruction.\nInline the synchronous free into the callback now that no direct callers\nremain."}],"metrics":[{"cvssV3_1":{"baseScore":7.8,"baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","version":"3.1"},"scenarios":[{"lang":"en","value":"AV:L - The trigger is a local rtnetlink RTM_NEWQDISC message (tc_modify_qdisc -> qdisc_create) with a clsact kind, a shared TCA_INGRESS_BLOCK and an invalid TCA_RATE. Packets only drive the reader side (tc_run), and no remote peer supplies the input that causes the bug.\nAC:L - The attacker controls both sides of the race: they repeat the failing clsact create, which runs qdisc_free() with no grace period, while pushing traffic through their own veth/dummy device so that tc_run() dereferences the published miniq. No outside condition is needed.\nPR:L - tc_modify_qdisc only needs CAP_NET_ADMIN in the netns that owns the device, which an unprivileged user gets through unshare -Urn plus a self-created veth/dummy interface. That makes it reachable as PR:L rather than requiring init-namespace root.\nUI:N - The attacker performs every step themselves: creating the shared block and filter, sending the failing RTM_NEWQDISC, and generating traffic. No victim action is needed.\nS:U - The use-after-free and any resulting privilege escalation stay inside the same kernel security authority. No hypervisor or IOMMU boundary is crossed.\nC:H - The mini_Qdisc embedded in the freed qdisc (a kmalloc'd object, so its slot can be reclaimed) is read by tc_run: miniq->block and miniq->filter_list are passed to tcf_classify. With a sprayed replacement object, the attacker controls these pointers, which can be used to leak kernel memory.\nI:H - tc_run calls mini_qdisc_bstats_cpu_update(), which writes through the cpu_bstats pointer taken from the freed object, and tcf_classify follows a filter_list the attacker can control. After reclaim, this gives a controlled write and a path to hijacking control flow.\nA:H - Freeing the qdisc while RCU readers in tc_run still hold its embedded miniq leads to KASAN splats and oopses when the packet path touches the freed or reallocated memory. The result is a kernel crash."}]}],"providerMetadata":{"dateUpdated":"2026-09-25T14:41:50.690Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/20bf6fa34b345333971bd4464a322cce87b83f4e"},{"url":"https://git.kernel.org/stable/c/156a3bab69744e9225bb9eff8c5cc53da18d5a2e"},{"url":"https://git.kernel.org/stable/c/5bfe927c5b4b290fad529186218c728589b4b101"},{"url":"https://git.kernel.org/stable/c/e6662f2100f8d33b0f4d0047c219efd6bba186ea"}],"title":"net/sched: defer qdisc freeing after failed creation","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-98017","datePublished":"2026-09-25T10:23:39.107Z","dateReserved":"2026-09-25T10:19:56.069Z","dateUpdated":"2026-09-25T14:41:50.690Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-09-25 11:17:30","lastModifiedDate":"2026-09-25 15:18:03","problem_types":[],"metrics":{"cvssMetricV31":[{"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7.8,"baseSeverity":"HIGH","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"},"exploitabilityScore":1.8,"impactScore":5.9}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"98017","Ordinal":"1","Title":"net/sched: defer qdisc freeing after failed creation","CVE":"CVE-2026-98017","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"98017","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: defer qdisc freeing after failed creation\n\nAn RTM_NEWQDISC request can make clsact bind a populated shared ingress\nblock during ->init(), publishing an embedded mini_Qdisc to lockless\nreaders.  If the same request has an invalid TCA_RATE, estimator setup\nfails after ->init(); the unwind removes the pointer but synchronously\nfrees its containing qdisc while tc_run() may still hold it.\n\nRetire failed qdiscs through the same RCU helper as normal destruction.\nInline the synchronous free into the callback now that no direct callers\nremain.","Type":"Description","Title":"net/sched: defer qdisc freeing after failed creation"}]}}}