{"id":"AZL-97356","summary":"CVE-2026-74615 affecting package kernel 6.6.150.1-1","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nvxlan: do not arm the ageing timer on a device that is down\n\nvxlan_changelink() arms vxlan-\u003eage_timer whenever the requested ageing\ninterval differs from the configured one:\n\n\tif (conf.age_interval != vxlan-\u003ecfg.age_interval)\n\t\tmod_timer(&vxlan-\u003eage_timer, jiffies);\n\nThere is no netif_running() test, so the timer is armed even on a device\nthat was never brought up.  The only synchronous cancel in the driver is\nthe timer_delete_sync() in vxlan_stop(), which is .ndo_stop.\nnetif_close_many() drops devices without IFF_UP before\n__dev_close_many() runs, so that cancel is skipped for such a device.\n\nvxlan_setup() sets dev-\u003eneeds_free_netdev = true and age_timer is a\nmember of struct vxlan_dev, so free_netdev() releases the allocation the\ntimer lives in while it is still queued on a timer_base.\nexpire_timers() unlinks the entry before it loads timer-\u003efunction, so\nthe timer core writes through the freed object's list pointers:\n\n  BUG: KASAN: slab-use-after-free in __run_timers+0x208/0x654\n  Write of size 8 at addr ffff00001adace68 by task true/192\n   __asan_store8+0x84/0xac\n   __run_timers+0x208/0x654\n   run_timer_softirq+0x154/0x18c\n  Allocated by task 189:\n   alloc_netdev_mqs+0x64/0x720\n   rtnl_create_link+0x4ac/0x520\n   rtnl_newlink+0x758/0xd00\n  Freed by task 191:\n   netdev_release+0x40/0x58\n   netdev_run_todo+0x4a4/0x8c0\n   rtnl_dellink+0x200/0x4e8\n\nThe rtnl operations involved are netns-scoped, so an unprivileged user\ncan perform them in a new user and network namespace.\n\nArming the timer on a down device never had an effect: vxlan_cleanup()\nreturns early on !netif_running(), and vxlan_open() arms the timer for\nany non-zero interval once the device is brought up.  Add the missing\ntest.\n\nDiscovered by XBOW, triaged by Baul Lee \u003cbaul.lee@xbow.com\u003e","modified":"2026-09-14T17:34:05Z","published":"2026-08-22T16:16:34Z","upstream":["CVE-2026-74615"],"references":[{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-74615"}],"affected":[{"package":{"name":"kernel","ecosystem":"Azure Linux:3","purl":"pkg:rpm/azure-linux/kernel"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"last_affected":"6.6.150.1-1"}]}],"database_specific":{"source":"https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-97356.json"}}],"schema_version":"1.9.0"}