{"id":"CVE-2026-64121","summary":"net: ifb: report ethtool stats over num_tx_queues","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: ifb: report ethtool stats over num_tx_queues\n\nifb_dev_init() allocates dp-\u003etx_private to dev-\u003enum_tx_queues\nentries via kzalloc_objs(*txp, dev-\u003enum_tx_queues). Both IFB\nper-queue RX and TX stats live in those entries: ifb_xmit() updates\ntxp-\u003erx_stats using the skb queue mapping, ifb_ri_tasklet() updates\ntxp-\u003etx_stats, and ifb_stats64() aggregates both over\ndev-\u003enum_tx_queues.\n\nThe ethtool stats callbacks instead size and walk the per-queue\nstats with dev-\u003ereal_num_rx_queues and dev-\u003ereal_num_tx_queues. With\nan asymmetric device where the RX queue count exceeds the TX queue\ncount, for example:\n\n    ip link add name ifb10 numtxqueues 1 numrxqueues 8 type ifb\n    ethtool -S ifb10\n\nifb_get_ethtool_stats() indexes past the tx_private allocation and\ncopies adjacent slab data through ETHTOOL_GSTATS.\n\nUse dev-\u003enum_tx_queues consistently for the stats strings, the\nstats count, and the stats data walks. This reports one RX stats\ngroup and one TX stats group for each backing ifb_q_private entry,\nwhich is the queue set IFB can actually populate.\n\nReproduced under UML+KASAN at v7.1-rc2:\n\n  BUG: KASAN: slab-out-of-bounds in ifb_fill_stats_data+0x3c/0xae\n  Read of size 8 at addr 0000000062dbd228 by task ethtool/36\n  ifb_fill_stats_data+0x3c/0xae\n  ifb_get_ethtool_stats+0xc0/0x129\n  __dev_ethtool+0x1ca5/0x363c\n  dev_ethtool+0x123/0x1b3\n  dev_ioctl+0x56c/0x744\n  sock_do_ioctl+0x15f/0x1b2\n  sock_ioctl+0x4d5/0x50a\n  sys_ioctl+0xd8b/0xde9\n\nWith the patch applied, the same UML+KASAN repro is silent and\nethtool -S ifb10 reports only the stats backed by the single\nallocated tx_private entry.","modified":"2026-11-07T02:30:39.597111953Z","published":"2026-07-19T15:40:19.745Z","related":["SUSE-SU-2026:23477-1","SUSE-SU-2026:23481-1","SUSE-SU-2026:23528-1","SUSE-SU-2026:23529-1","SUSE-SU-2026:23881-1","SUSE-SU-2026:23887-1","SUSE-SU-2026:23897-1","SUSE-SU-2026:23902-1","SUSE-SU-2026:23993-1","SUSE-SU-2026:23994-1","SUSE-SU-2026:23995-1","SUSE-SU-2026:23996-1","SUSE-SU-2026:23997-1","SUSE-SU-2026:23998-1","SUSE-SU-2026:23999-1","SUSE-SU-2026:24000-1","SUSE-SU-2026:24001-1","SUSE-SU-2026:24002-1","SUSE-SU-2026:24003-1","SUSE-SU-2026:24004-1","SUSE-SU-2026:24005-1","SUSE-SU-2026:24006-1","SUSE-SU-2026:24007-1","SUSE-SU-2026:24008-1","SUSE-SU-2026:24009-1","SUSE-SU-2026:24010-1","SUSE-SU-2026:24016-1","SUSE-SU-2026:24022-1","SUSE-SU-2026:24023-1","SUSE-SU-2026:24024-1","SUSE-SU-2026:24025-1","SUSE-SU-2026:24026-1","SUSE-SU-2026:24027-1","SUSE-SU-2026:24028-1","SUSE-SU-2026:24029-1","SUSE-SU-2026:24030-1","SUSE-SU-2026:24031-1","SUSE-SU-2026:24032-1","SUSE-SU-2026:24033-1","SUSE-SU-2026:24034-1","SUSE-SU-2026:24035-1","SUSE-SU-2026:24036-1","SUSE-SU-2026:24037-1","SUSE-SU-2026:24038-1","SUSE-SU-2026:24040-1","SUSE-SU-2026:24041-1","SUSE-SU-2026:24042-1","SUSE-SU-2026:24043-1","SUSE-SU-2026:24044-1","SUSE-SU-2026:24045-1","SUSE-SU-2026:24046-1","SUSE-SU-2026:24047-1","SUSE-SU-2026:24048-1","SUSE-SU-2026:24049-1","SUSE-SU-2026:24050-1","SUSE-SU-2026:24051-1","SUSE-SU-2026:24052-1","SUSE-SU-2026:24053-1","SUSE-SU-2026:24054-1","SUSE-SU-2026:24058-1","SUSE-SU-2026:24059-1","SUSE-SU-2026:24060-1","SUSE-SU-2026:24061-1","SUSE-SU-2026:24062-1","SUSE-SU-2026:24063-1","SUSE-SU-2026:24064-1","SUSE-SU-2026:24065-1","SUSE-SU-2026:24066-1","SUSE-SU-2026:24067-1","SUSE-SU-2026:24068-1","SUSE-SU-2026:24069-1","SUSE-SU-2026:24070-1","SUSE-SU-2026:24071-1","SUSE-SU-2026:24072-1","SUSE-SU-2026:24074-1","SUSE-SU-2026:24075-1","SUSE-SU-2026:24076-1","SUSE-SU-2026:24077-1","SUSE-SU-2026:24078-1","SUSE-SU-2026:24079-1","SUSE-SU-2026:24080-1","SUSE-SU-2026:24081-1","SUSE-SU-2026:24082-1","SUSE-SU-2026:24083-1","SUSE-SU-2026:24084-1","SUSE-SU-2026:24085-1","SUSE-SU-2026:24086-1","SUSE-SU-2026:24087-1","SUSE-SU-2026:24088-1","SUSE-SU-2026:24089-1","SUSE-SU-2026:24090-1","SUSE-SU-2026:24092-1","SUSE-SU-2026:24093-1","SUSE-SU-2026:24094-1","SUSE-SU-2026:24095-1","SUSE-SU-2026:24097-1","SUSE-SU-2026:24098-1","SUSE-SU-2026:24099-1","SUSE-SU-2026:24100-1","SUSE-SU-2026:24101-1","SUSE-SU-2026:24102-1","SUSE-SU-2026:24103-1","SUSE-SU-2026:24104-1","SUSE-SU-2026:24105-1","SUSE-SU-2026:24106-1","SUSE-SU-2026:24107-1","SUSE-SU-2026:24108-1","SUSE-SU-2026:24160-1","SUSE-SU-2026:24161-1","SUSE-SU-2026:24162-1","SUSE-SU-2026:24163-1","SUSE-SU-2026:24164-1","SUSE-SU-2026:24165-1","SUSE-SU-2026:24166-1","SUSE-SU-2026:24167-1","SUSE-SU-2026:24168-1","SUSE-SU-2026:24169-1","SUSE-SU-2026:24170-1","SUSE-SU-2026:24171-1","SUSE-SU-2026:24172-1","SUSE-SU-2026:24173-1","SUSE-SU-2026:24174-1","SUSE-SU-2026:24175-1","SUSE-SU-2026:4120-1","SUSE-SU-2026:4254-1","SUSE-SU-2026:4369-1","SUSE-SU-2026:4415-1","SUSE-SU-2026:4433-1","SUSE-SU-2026:4471-1","SUSE-SU-2026:4489-1","SUSE-SU-2026:4498-1","SUSE-SU-2026:4513-1","SUSE-SU-2026:4514-1","SUSE-SU-2026:4518-1","SUSE-SU-2026:4537-1","SUSE-SU-2026:4540-1","openSUSE-SU-2026:21910-1"],"database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64121.json","cna_assigner":"Linux"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/16bd798cb6d8337d7c3eea1adc412f31b5181d5b"},{"type":"WEB","url":"https://git.kernel.org/stable/c/2638e1773904d7aa8f24c6e7fda2ed7d69df6fa4"},{"type":"WEB","url":"https://git.kernel.org/stable/c/301a554e458e2f5ec47f2c336a7cb03b877f9fd6"},{"type":"WEB","url":"https://git.kernel.org/stable/c/5db89c99566fc4728cc92e941d8e1975711e24b5"},{"type":"WEB","url":"https://git.kernel.org/stable/c/6afdb8113cb007f9332f59a9b7fd45731b8a9de5"},{"type":"WEB","url":"https://git.kernel.org/stable/c/f8a5a76b4a683043c6eff2a060bcaa17f9316ad5"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64121.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-64121"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"a21ee5b2fcb8d6d3973446c5039e966c4cfe40d1"},{"fixed":"6afdb8113cb007f9332f59a9b7fd45731b8a9de5"},{"fixed":"16bd798cb6d8337d7c3eea1adc412f31b5181d5b"},{"fixed":"301a554e458e2f5ec47f2c336a7cb03b877f9fd6"},{"fixed":"f8a5a76b4a683043c6eff2a060bcaa17f9316ad5"},{"fixed":"2638e1773904d7aa8f24c6e7fda2ed7d69df6fa4"},{"fixed":"5db89c99566fc4728cc92e941d8e1975711e24b5"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-64121.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"5.17.0"},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