{"id":"CVE-2026-98234","revision":"bb61b4c8611e427f880c9d15685745d2","records":[{"revision":"bb61b4c8611e427f880c9d15685745d2","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-98234","aliases":[],"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":0,"publishedAt":"2026-10-06T08:45:07.215+00:00","modifiedAt":"2026-10-19T09:16:06.128+00:00","affected":[{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"unaffected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"net/sched/sch_hhf.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"10239edf86f137ce4c39b62ea9575e8053c549a0\",\n                            \"lessThan\": \"7adfd0a42174b85c6bd678858ecd6674f403f336\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"10239edf86f137ce4c39b62ea9575e8053c549a0\",\n                            \"lessThan\": \"35fd423a5c5132c6f4321f6c4f0a7b4b90af830c\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"10239edf86f137ce4c39b62ea9575e8053c549a0\",\n                            \"lessThan\": \"06d2a101e89063cb0b9b459104db48bdfb0a797d\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"10239edf86f137ce4c39b62ea9575e8053c549a0\",\n                            \"lessThan\": \"d8e2f1f0263b7c97b222c06070cccf13e0ab7112\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"10239edf86f137ce4c39b62ea9575e8053c549a0\",\n                            \"lessThan\": \"f3f4a5cb4a6e9b1f1f25d34dfc25f836a1601db4\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"10239edf86f137ce4c39b62ea9575e8053c549a0\",\n                            \"lessThan\": \"1731ff1d20489afe4cd01b7d16d37f324746ac54\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"10239edf86f137ce4c39b62ea9575e8053c549a0\",\n                            \"lessThan\": \"f6547d27ce2093c5627636fb63dd0b7523c466f9\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"10239edf86f137ce4c39b62ea9575e8053c549a0\",\n                            \"lessThan\": \"2cef2588c995722a901368def30befeef9ae55c6\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        }\n                    ]\n                }"},{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"affected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"net/sched/sch_hhf.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"3.14\",\n                            \"status\": \"affected\"\n                        },\n                        {\n                            \"version\": \"0\",\n                            \"lessThan\": \"3.14\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"5.10.271\",\n                            \"lessThanOrEqual\": \"5.10.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"5.15.222\",\n                            \"lessThanOrEqual\": \"5.15.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.1.189\",\n                            \"lessThanOrEqual\": \"6.1.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.6.158\",\n                            \"lessThanOrEqual\": \"6.6.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.12.112\",\n                            \"lessThanOrEqual\": \"6.12.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.18.54\",\n                            \"lessThanOrEqual\": \"6.18.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.2.8\",\n                            \"lessThanOrEqual\": \"7.2.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.3\",\n                            \"lessThanOrEqual\": \"*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"original_commit_for_fix\"\n                        }\n                    ]\n                }"}],"metrics":[],"references":["https://git.kernel.org/stable/c/7adfd0a42174b85c6bd678858ecd6674f403f336","https://git.kernel.org/stable/c/35fd423a5c5132c6f4321f6c4f0a7b4b90af830c","https://git.kernel.org/stable/c/06d2a101e89063cb0b9b459104db48bdfb0a797d","https://git.kernel.org/stable/c/d8e2f1f0263b7c97b222c06070cccf13e0ab7112","https://git.kernel.org/stable/c/f3f4a5cb4a6e9b1f1f25d34dfc25f836a1601db4","https://git.kernel.org/stable/c/1731ff1d20489afe4cd01b7d16d37f324746ac54","https://git.kernel.org/stable/c/f6547d27ce2093c5627636fb63dd0b7523c466f9","https://git.kernel.org/stable/c/2cef2588c995722a901368def30befeef9ae55c6"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-98234","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-98234","identifiers":["CVE-2026-98234"]},"retained":false,"historicalAffected":[]}],"coverage":[]}