{"id":"AZL-108792","summary":"CVE-2026-98567 affecting package kernel 6.6.157.1-1","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: xps: reject an out of range traffic class\n\nOnly the entries below dev-\u003enum_tc are valid in dev-\u003etc_to_txq[], and\ndev-\u003eprio_tc_map[] may only name classes below it. netdev_set_num_tc()\nlowers dev-\u003enum_tc without touching either array.\n\nnetdev_txq_to_tc() walks all TC_MAX_QUEUE slots and\nnetdev_get_prio_tc_map() returns the entry as it stands, so a leftover\nentry is handed out as a traffic class \u003e= dev-\u003enum_tc. Taking that\nclass from netdev_txq_to_tc(), __netif_set_xps_queue() rejects only a\nnegative one and indexes an XPS map sized for dev-\u003enum_tc classes:\n\n\ttci = j * num_tc + tc;\n\tRCU_INIT_POINTER(new_dev_maps-\u003eattr_map[tci], map);\n\nattr_map[] holds nr_ids * num_tc entries and j runs over the ids named\nin the mask, so a class that is not below num_tc pushes tci past the end\nof the map for the last ids and the store overruns it.\n\nAny caller that lowers num_tc leaves such entries behind, and\nmqprio_destroy() tears down with netdev_set_num_tc(dev, 0) rather than\nnetdev_reset_tc(). After mqprio with 8 classes then 1, tc_to_txq[1..7]\nstill describe txq 1..7. The splat is from an XPS write to txq 2 on a\nveth with 8 rx queues: attr_map[] has 8 * 1 entries, tci = j + 2, and\nj == 6 stores one past the end of the 88-byte map:\n\n  BUG: KASAN: slab-out-of-bounds in __netif_set_xps_queue (net/core/dev.c:2954)\n  Write of size 8 at addr ffff88813016bc58 by task xps_oob/634\n   __netif_set_xps_queue (net/core/dev.c:2954)\n   xps_rxqs_store (net/core/net-sysfs.c:1880)\n   netdev_queue_attr_store (net/core/net-sysfs.c:1390)\n  Allocated by task 634:\n   __kmalloc_noprof (mm/slub.c:5439)\n   __netif_set_xps_queue (net/core/dev.c:2937)\n  The buggy address is located 0 bytes to the right of\n   allocated 88-byte region [ffff88813016bc00, ffff88813016bc58)\n\nReject a class the map has no room for.","modified":"2026-10-19T14:17:05.634781471Z","published":"2026-10-18T16:17:08Z","upstream":["CVE-2026-98567"],"references":[{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-98567"}],"affected":[{"package":{"name":"kernel","ecosystem":"Azure Linux:3","purl":"pkg:rpm/azure-linux/kernel"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"last_affected":"6.6.157.1-1"}]}],"database_specific":{"source":"https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-108792.json"}}],"schema_version":"1.9.0"}