{"api_version":"1","generated_at":"2026-10-09T17:55:38+00:00","cve":"CVE-2026-98234","urls":{"html":"https://cve.report/CVE-2026-98234","api":"https://cve.report/api/cve/CVE-2026-98234.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-98234","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-98234"},"summary":{"title":"net/sched: hhf: cap hh_flows_limit at change time","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: hhf: cap hh_flows_limit at change time\n\nhhf_change() stores TCA_HHF_HH_FLOWS_LIMIT with no upper bound. A huge\nhh_flows_limit lets each new heavy-hitter flow pass the\nhh_flows_current_cnt check in alloc_new_hh() and forces a fixed-size\nkzalloc(GFP_ATOMIC) per flow under spoofed traffic, for unbounded memory\ngrowth.\n\nBound the attribute with NLA_POLICY_MAX() at 2*HH_FLOWS_CNT (the\nhhf_init() default) and report the rejected value via extack. The\ndeprecated nested parse is kept: legacy tc does not set NLA_F_NESTED on\nTCA_OPTIONS. Configs relying on hh_limit above the default were relying\non unbounded, unsafe behaviour and are not supported going forward.\n\nhhf_init() also ran hhf_change() before setting the default\nhh_flows_limit, so a user-supplied hh_limit at add time was clobbered\nback to 2048. Set the default before hhf_change() so the configured\nvalue sticks.\n\nThis is a follow-up to commit eb56a495f59b (\"net/sched: hhf: clamp\nquantum in change and init paths\"), which bounded the quantum of the\nsame qdisc; the hh_flows_limit bound is the remaining unbounded knob of\nthat series' scope.\n\nConditions to recreate the bug: CAP_NET_ADMIN in a user namespace;\ntc qdisc change dev X root hhf hh_limit 4294967295 succeeds and the\nvalue is echoed by tc qdisc show, unbounding heavy-hitter flow\nallocations; also tc qdisc add dev X root hhf hh_limit 500 stores 2048\ninstead of 500.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-10-06 09:18:11","updated_at":"2026-10-06 09:18:11"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/f6547d27ce2093c5627636fb63dd0b7523c466f9","name":"https://git.kernel.org/stable/c/f6547d27ce2093c5627636fb63dd0b7523c466f9","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/35fd423a5c5132c6f4321f6c4f0a7b4b90af830c","name":"https://git.kernel.org/stable/c/35fd423a5c5132c6f4321f6c4f0a7b4b90af830c","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/7adfd0a42174b85c6bd678858ecd6674f403f336","name":"https://git.kernel.org/stable/c/7adfd0a42174b85c6bd678858ecd6674f403f336","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/06d2a101e89063cb0b9b459104db48bdfb0a797d","name":"https://git.kernel.org/stable/c/06d2a101e89063cb0b9b459104db48bdfb0a797d","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/1731ff1d20489afe4cd01b7d16d37f324746ac54","name":"https://git.kernel.org/stable/c/1731ff1d20489afe4cd01b7d16d37f324746ac54","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/2cef2588c995722a901368def30befeef9ae55c6","name":"https://git.kernel.org/stable/c/2cef2588c995722a901368def30befeef9ae55c6","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/d8e2f1f0263b7c97b222c06070cccf13e0ab7112","name":"https://git.kernel.org/stable/c/d8e2f1f0263b7c97b222c06070cccf13e0ab7112","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/f3f4a5cb4a6e9b1f1f25d34dfc25f836a1601db4","name":"https://git.kernel.org/stable/c/f3f4a5cb4a6e9b1f1f25d34dfc25f836a1601db4","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-98234","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-98234","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 10239edf86f137ce4c39b62ea9575e8053c549a0 7adfd0a42174b85c6bd678858ecd6674f403f336 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 10239edf86f137ce4c39b62ea9575e8053c549a0 35fd423a5c5132c6f4321f6c4f0a7b4b90af830c git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 10239edf86f137ce4c39b62ea9575e8053c549a0 06d2a101e89063cb0b9b459104db48bdfb0a797d git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 10239edf86f137ce4c39b62ea9575e8053c549a0 d8e2f1f0263b7c97b222c06070cccf13e0ab7112 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 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semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.15.222 5.15.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.1.189 6.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.6.158 6.6.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.112 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.54 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2.8 7.2.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.3-rc4 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"98234","cve":"CVE-2026-98234","epss":"0.002200000","percentile":"0.113620000","score_date":"2026-10-06","updated_at":"2026-10-07 00:14:55"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["net/sched/sch_hhf.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"7adfd0a42174b85c6bd678858ecd6674f403f336","status":"affected","version":"10239edf86f137ce4c39b62ea9575e8053c549a0","versionType":"git"},{"lessThan":"35fd423a5c5132c6f4321f6c4f0a7b4b90af830c","status":"affected","version":"10239edf86f137ce4c39b62ea9575e8053c549a0","versionType":"git"},{"lessThan":"06d2a101e89063cb0b9b459104db48bdfb0a797d","status":"affected","version":"10239edf86f137ce4c39b62ea9575e8053c549a0","versionType":"git"},{"lessThan":"d8e2f1f0263b7c97b222c06070cccf13e0ab7112","status":"affected","version":"10239edf86f137ce4c39b62ea9575e8053c549a0","versionType":"git"},{"lessThan":"f3f4a5cb4a6e9b1f1f25d34dfc25f836a1601db4","status":"affected","version":"10239edf86f137ce4c39b62ea9575e8053c549a0","versionType":"git"},{"lessThan":"1731ff1d20489afe4cd01b7d16d37f324746ac54","status":"affected","version":"10239edf86f137ce4c39b62ea9575e8053c549a0","versionType":"git"},{"lessThan":"f6547d27ce2093c5627636fb63dd0b7523c466f9","status":"affected","version":"10239edf86f137ce4c39b62ea9575e8053c549a0","versionType":"git"},{"lessThan":"2cef2588c995722a901368def30befeef9ae55c6","status":"affected","version":"10239edf86f137ce4c39b62ea9575e8053c549a0","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["net/sched/sch_hhf.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"3.14"},{"lessThan":"3.14","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"5.10.*","status":"unaffected","version":"5.10.271","versionType":"semver"},{"lessThanOrEqual":"5.15.*","status":"unaffected","version":"5.15.222","versionType":"semver"},{"lessThanOrEqual":"6.1.*","status":"unaffected","version":"6.1.189","versionType":"semver"},{"lessThanOrEqual":"6.6.*","status":"unaffected","version":"6.6.158","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.112","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.54","versionType":"semver"},{"lessThanOrEqual":"7.2.*","status":"unaffected","version":"7.2.8","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.3-rc4","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"5.10.271","versionStartIncluding":"3.14","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"5.15.222","versionStartIncluding":"3.14","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.1.189","versionStartIncluding":"3.14","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.6.158","versionStartIncluding":"3.14","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.112","versionStartIncluding":"3.14","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.54","versionStartIncluding":"3.14","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2.8","versionStartIncluding":"3.14","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.3-rc4","versionStartIncluding":"3.14","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: hhf: cap hh_flows_limit at change time\n\nhhf_change() stores TCA_HHF_HH_FLOWS_LIMIT with no upper bound. A huge\nhh_flows_limit lets each new heavy-hitter flow pass the\nhh_flows_current_cnt check in alloc_new_hh() and forces a fixed-size\nkzalloc(GFP_ATOMIC) per flow under spoofed traffic, for unbounded memory\ngrowth.\n\nBound the attribute with NLA_POLICY_MAX() at 2*HH_FLOWS_CNT (the\nhhf_init() default) and report the rejected value via extack. The\ndeprecated nested parse is kept: legacy tc does not set NLA_F_NESTED on\nTCA_OPTIONS. Configs relying on hh_limit above the default were relying\non unbounded, unsafe behaviour and are not supported going forward.\n\nhhf_init() also ran hhf_change() before setting the default\nhh_flows_limit, so a user-supplied hh_limit at add time was clobbered\nback to 2048. Set the default before hhf_change() so the configured\nvalue sticks.\n\nThis is a follow-up to commit eb56a495f59b (\"net/sched: hhf: clamp\nquantum in change and init paths\"), which bounded the quantum of the\nsame qdisc; the hh_flows_limit bound is the remaining unbounded knob of\nthat series' scope.\n\nConditions to recreate the bug: CAP_NET_ADMIN in a user namespace;\ntc qdisc change dev X root hhf hh_limit 4294967295 succeeds and the\nvalue is echoed by tc qdisc show, unbounding heavy-hitter flow\nallocations; also tc qdisc add dev X root hhf hh_limit 500 stores 2048\ninstead of 500."}],"providerMetadata":{"dateUpdated":"2026-10-06T08:45:07.215Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/7adfd0a42174b85c6bd678858ecd6674f403f336"},{"url":"https://git.kernel.org/stable/c/35fd423a5c5132c6f4321f6c4f0a7b4b90af830c"},{"url":"https://git.kernel.org/stable/c/06d2a101e89063cb0b9b459104db48bdfb0a797d"},{"url":"https://git.kernel.org/stable/c/d8e2f1f0263b7c97b222c06070cccf13e0ab7112"},{"url":"https://git.kernel.org/stable/c/f3f4a5cb4a6e9b1f1f25d34dfc25f836a1601db4"},{"url":"https://git.kernel.org/stable/c/1731ff1d20489afe4cd01b7d16d37f324746ac54"},{"url":"https://git.kernel.org/stable/c/f6547d27ce2093c5627636fb63dd0b7523c466f9"},{"url":"https://git.kernel.org/stable/c/2cef2588c995722a901368def30befeef9ae55c6"}],"title":"net/sched: hhf: cap hh_flows_limit at change time","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-98234","datePublished":"2026-10-06T08:45:07.215Z","dateReserved":"2026-09-25T10:25:14.329Z","dateUpdated":"2026-10-06T08:45:07.215Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-10-06 09:18:11","lastModifiedDate":"2026-10-06 09:18:11","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"98234","Ordinal":"1","Title":"net/sched: hhf: cap hh_flows_limit at change time","CVE":"CVE-2026-98234","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"98234","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: hhf: cap hh_flows_limit at change time\n\nhhf_change() stores TCA_HHF_HH_FLOWS_LIMIT with no upper bound. A huge\nhh_flows_limit lets each new heavy-hitter flow pass the\nhh_flows_current_cnt check in alloc_new_hh() and forces a fixed-size\nkzalloc(GFP_ATOMIC) per flow under spoofed traffic, for unbounded memory\ngrowth.\n\nBound the attribute with NLA_POLICY_MAX() at 2*HH_FLOWS_CNT (the\nhhf_init() default) and report the rejected value via extack. The\ndeprecated nested parse is kept: legacy tc does not set NLA_F_NESTED on\nTCA_OPTIONS. Configs relying on hh_limit above the default were relying\non unbounded, unsafe behaviour and are not supported going forward.\n\nhhf_init() also ran hhf_change() before setting the default\nhh_flows_limit, so a user-supplied hh_limit at add time was clobbered\nback to 2048. Set the default before hhf_change() so the configured\nvalue sticks.\n\nThis is a follow-up to commit eb56a495f59b (\"net/sched: hhf: clamp\nquantum in change and init paths\"), which bounded the quantum of the\nsame qdisc; the hh_flows_limit bound is the remaining unbounded knob of\nthat series' scope.\n\nConditions to recreate the bug: CAP_NET_ADMIN in a user namespace;\ntc qdisc change dev X root hhf hh_limit 4294967295 succeeds and the\nvalue is echoed by tc qdisc show, unbounding heavy-hitter flow\nallocations; also tc qdisc add dev X root hhf hh_limit 500 stores 2048\ninstead of 500.","Type":"Description","Title":"net/sched: hhf: cap hh_flows_limit at change time"}]}}}