{"id":"CVE-2026-98629","summary":"net/sched: cls_u32: fix manual hash table handle IDR aliasing","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: cls_u32: fix manual hash table handle IDR aliasing\n\nA u32 hash table created with an explicit handle ('tc filter add ...\nhandle 801: u32 divisor N') keys its IDR entry on the raw handle, while\nthe destroy paths free it under handle2id(handle). The two key domains\ndisagree for handles in the 0x800..0xFFF htid range:\nhandle2id() folds them back into the auto-allocated id space (1..0x7FF).\n\nA manual table therefore leaves its raw-keyed IDR entry unreachable on\ndelete (a permanent leak), and its delete can drop the idr entry of an\nunrelated live auto table. A later auto allocation can then hand out a\nhandle that aliases the live manual table; u32_lookup_ht() first-match\nroutes lookups and TCA_U32_LINK for that htid to the wrong table.\n\nKey the divisor-path alloc on handle2id(handle) so allocation and\nremoval share one key domain. A manual handle that maps onto an id\nalready in use is rejected with -ENOSPC, and auto allocation skips ids\nheld by live manual tables.\n\nConditions to recreate:\n  ip link add test0 type dummy\n  tc qdisc add dev test0 clsact\n  tc filter add dev test0 ingress protocol ip pref 1 \\\n          handle 801: u32 divisor 16\n  tc filter add dev test0 ingress protocol ip pref 2 u32 divisor 16\n  tc -d filter show dev test0 ingress | grep 'fh 801:'\n  # unpatched: two live tables with handle 0x80100000 (the pref 2 root\n  # hnode is auto-allocated id 1); patched: the auto hnode takes id 2.\n\nAlso tested with a poc with a live u32 table on the block, add/delete a manual\ntable 'handle 901: u32 divisor 1' twice; unpatched, the re-add fails with\n-ENOSPC because the raw key leaked on the first delete.","modified":"2026-10-19T02:46:58.271042039Z","published":"2026-10-18T15:19:50.589Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/98xxx/CVE-2026-98629.json","cna_assigner":"Linux"},"references":[{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"},{"type":"WEB","url":"https://git.kernel.org/stable/c/0a5f5d9e94dead312d32c366b917c64e552b72f7"},{"type":"WEB","url":"https://git.kernel.org/stable/c/0fac292d93fdb313099e98cce928b3a524c92c94"},{"type":"WEB","url":"https://git.kernel.org/stable/c/21fc07924e996e1e661268ca269c86b8d59d25b3"},{"type":"WEB","url":"https://git.kernel.org/stable/c/2f898f9ec7c73c5697ee462681e7ea6984ee1f3d"},{"type":"WEB","url":"https://git.kernel.org/stable/c/54a454c5e41f5e2cb70c8163140ce095c5d5eefd"},{"type":"WEB","url":"https://git.kernel.org/stable/c/f6696481eedfd5752b4b56eed715d0b0fe48b9c5"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/98xxx/CVE-2026-98629.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-98629"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"9b2c3184e126b941dfa716b8128ed6db92a64e2f"},{"fixed":"21fc07924e996e1e661268ca269c86b8d59d25b3"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"789f9963bd031c3a185605665b744912df8e7eda"},{"fixed":"0fac292d93fdb313099e98cce928b3a524c92c94"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"73af53d82076bbe184d9ece9e14b0dc8599e6055"},{"fixed":"54a454c5e41f5e2cb70c8163140ce095c5d5eefd"},{"fixed":"f6696481eedfd5752b4b56eed715d0b0fe48b9c5"},{"fixed":"2f898f9ec7c73c5697ee462681e7ea6984ee1f3d"},{"fixed":"0a5f5d9e94dead312d32c366b917c64e552b72f7"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"6.1.119"},{"fixed":"6.1.189"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"6.6.63"},{"fixed":"6.6.158"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"6.11.10"},{"fixed":"6.12"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"4403f9293ce9ecc2a55c688d84ee37e3ba0fc1a8"}]}],"versions":["v6.1.188","v6.1.187","v6.1.186","v6.1.185","v6.1.184","v6.1.183","v6.1.182","v6.1.181","v6.1.180","v6.1.179","v6.1.178","v6.1.177","v6.1.176","v6.1.175","v6.1.174","v6.1.173","v6.1.172","v6.1.171","v6.1.170","v6.1.169","v6.1.168","v6.1.167","v6.1.166","v6.1.165","v6.1.164","v6.1.163","v6.1.162","v6.1.161","v6.1.160","v6.1.159","v6.1.158","v6.1.157","v6.1.156","v6.1.155","v6.1.154","v6.1.153","v6.1.152","v6.1.151","v6.1.150","v6.1.149","v6.1.148","v6.1.147","v6.1.146","v6.1.145","v6.1.144","v6.1.143","v6.1.142","v6.1.141","v6.1.140","v6.1.139","v6.1.138","v6.1.137","v6.1.136","v6.1.135","v6.1.134","v6.1.133","v6.1.132","v6.1.131","v6.1.130","v6.1.129","v6.1.128","v6.1.127","v6.1.126","v6.1.125","v6.1.124","v6.1.123","v6.1.122","v6.1.121","v6.1.120","v6.1.119","v6.6.157","v6.6.156","v6.6.155","v6.6.154","v6.6.153","v6.6.152","v6.6.151","v6.6.150","v6.6.149","v6.6.148","v6.6.147","v6.6.146","v6.6.145","v6.6.144","v6.6.143","v6.6.142","v6.6.141","v6.6.140","v6.6.139","v6.6.138","v6.6.137","v6.6.136","v6.6.135","v6.6.134","v6.6.133","v6.6.132","v6.6.131","v6.6.130","v6.6.129","v6.6.128","v6.6.127","v6.6.126","v6.6.125","v6.6.124","v6.6.123","v6.6.122","v6.6.121","v6.6.120","v6.6.119","v6.6.118","v6.6.117","v6.6.116","v6.6.115","v6.6.114","v6.6.113","v6.6.112","v6.6.111","v6.6.110","v6.6.109","v6.6.108","v6.6.107","v6.6.106","v6.6.105","v6.6.104","v6.6.103","v6.6.102","v6.6.101","v6.6.100","v6.6.99","v6.6.98","v6.6.97","v6.6.96","v6.6.95","v6.6.94","v6.6.93","v6.6.92","v6.6.91","v6.6.90","v6.6.89","v6.6.88","v6.6.87","v6.6.86","v6.6.85","v6.6.84","v6.6.83","v6.6.82","v6.6.81","v6.6.80","v6.6.79","v6.6.78","v6.6.77","v6.6.76","v6.6.75","v6.6.74","v6.6.73","v6.6.72","v6.6.71","v6.6.70","v6.6.69","v6.6.68","v6.6.67","v6.6.66","v6.6.65","v6.6.64","v6.6.63","v6.11.11","v6.11.10"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-98629.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.1.189"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.6.158"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.112"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.12.0"},{"fixed":"6.18.55"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"7.2.9"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-98629.json"}}],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