{"id":"CVE-2026-97959","revision":"5a79134ee13841499440fc3fcf34a675","records":[{"revision":"5a79134ee13841499440fc3fcf34a675","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-97959","aliases":[],"title":"net/sched: cls_route: free emptied bucket on filter move","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: cls_route: free emptied bucket on filter move\n\nroute4_change can move an existing filter to a different top-level\nbucket: route4_set_parms recomputes the handle from TCA_ROUTE4_TO/\nFROM/IIF, and the handle-mismatch check is gated on the 'new' flag, so\nfor an existing filter the new handle may differ from the old one and\nland in a different bucket. When this happens, the filter is unlinked\nfrom the old bucket, but the bucket itself is never freed once it goes\nempty. The stale empty bucket remains in head->table[], causing\nroute4_delete to report *last=false even after the last live filter is\ngone. That pins the empty tcf_proto and causes a leak.\n\nFix this by refcounting the filters linked to a bucket and freeing the\nbucket when the count drops to zero. The existing scan in route4_delete\ngoes away with it.\n\nThe count is updated at all sites that link or unlink a filter during add,\nchange and delete, and the bucket is dropped from head->table[] as soon as\nit reaches zero.\n\nConditions to recreate the bug:\n  CONFIG_NET_CLS_ROUTE4=y, CONFIG_NET_SCH_INGRESS=y, CONFIG_NET_CLS_ACT=y.\n\n  tc qdisc replace dev lo clsact\n  tc filter add dev lo ingress protocol ip pref 100 route from 1 to 1\n  tc filter change dev lo ingress protocol ip pref 100 handle 0x10001 \\\n    route from 1 to 2\n  tc filter del dev lo ingress protocol ip pref 100 handle 0x10002 \\\n    route from 1 to 2\n  tc filter show dev lo ingress | grep -c 'pref 100 route chain 0 '","state":0,"publishedAt":"2026-09-25T10:23:04.348+00:00","modifiedAt":"2026-10-19T09:11:25.255+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/cls_route.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"1e052be69d045c8d0f82ff1116fd3e5a79661745\",\n                            \"lessThan\": \"9e7741b41a25b9d49df4d262fa314342e6f95c50\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"1e052be69d045c8d0f82ff1116fd3e5a79661745\",\n                            \"lessThan\": \"48d38bf8c22a05fde07ba1f885cde27b851649a2\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"1e052be69d045c8d0f82ff1116fd3e5a79661745\",\n                            \"lessThan\": \"cc99d26b12431e4e4d0e346ec32764eb42c0aed9\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"1e052be69d045c8d0f82ff1116fd3e5a79661745\",\n                            \"lessThan\": \"41e94079200aaf0cdbe4594b0af75710b33da124\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"1e052be69d045c8d0f82ff1116fd3e5a79661745\",\n                            \"lessThan\": \"2e2f130951d34871b0643bf700164d97cff4b427\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"1e052be69d045c8d0f82ff1116fd3e5a79661745\",\n                            \"lessThan\": \"f8495d67434e1cb7e511297687ca55fdb28e4c20\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"1e052be69d045c8d0f82ff1116fd3e5a79661745\",\n                            \"lessThan\": \"81dd117c04422c6d0c7974aba9fa6a0ba370959b\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"1e052be69d045c8d0f82ff1116fd3e5a79661745\",\n                            \"lessThan\": \"1853f30cf5c84971f99788a76207c6f745380896\",\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/cls_route.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"4.1\",\n                            \"status\": \"affected\"\n                        },\n                        {\n                            \"version\": \"0\",\n                            \"lessThan\": \"4.1\",\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\": \"6.12.111\",\n                            \"lessThanOrEqual\": \"6.12.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.18.53\",\n                            \"lessThanOrEqual\": \"6.18.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.2.7\",\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/9e7741b41a25b9d49df4d262fa314342e6f95c50","https://git.kernel.org/stable/c/48d38bf8c22a05fde07ba1f885cde27b851649a2","https://git.kernel.org/stable/c/cc99d26b12431e4e4d0e346ec32764eb42c0aed9","https://git.kernel.org/stable/c/41e94079200aaf0cdbe4594b0af75710b33da124","https://git.kernel.org/stable/c/2e2f130951d34871b0643bf700164d97cff4b427","https://git.kernel.org/stable/c/f8495d67434e1cb7e511297687ca55fdb28e4c20","https://git.kernel.org/stable/c/81dd117c04422c6d0c7974aba9fa6a0ba370959b","https://git.kernel.org/stable/c/1853f30cf5c84971f99788a76207c6f745380896"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-97959","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-97959","identifiers":["CVE-2026-97959"]},"retained":false,"historicalAffected":[]}],"coverage":[]}