{"id":"AZL-94859","summary":"CVE-2026-68169 affecting package kernel 6.6.150.1-1","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nmptcp: pm: userspace: fix use-after-free in get_local_id\n\nIn mptcp_pm_userspace_get_local_id(), the address entry is looked up under\nspinlock, but its id is read after dropping the lock. A concurrent deletion\ncan free the entry between the unlock and the read, leading to UAF.\n\nThe race window is narrow. It was reproduced only with a locally\nconstructed stress test that repeatedly overlaps an MP_JOIN SYN with a\nMPTCP_PM_CMD_SUBFLOW_DESTROY request.\n\nHowever, the KASAN report below confirms that the race is reachable:\n\n  [  666.319376] BUG: KASAN: slab-use-after-free in mptcp_userspace_pm_get_local_id+0x1dc/0x1f0\n  [  666.319386] Read of size 1 at addr ffff888124845610 by task swapper/0/0\n  ...\n  [  666.319401] Call Trace:\n  [  666.319405]  \u003cIRQ\u003e\n  [  666.319408]  dump_stack_lvl+0x53/0x70\n  [  666.319412]  print_address_description.constprop.0+0x2c/0x3b0\n  [  666.319418]  print_report+0xbe/0x2b0\n  [  666.319421]  ? mptcp_userspace_pm_get_local_id+0x1dc/0x1f0\n  [  666.319423]  kasan_report+0xce/0x100\n  [  666.319426]  ? mptcp_userspace_pm_get_local_id+0x1dc/0x1f0\n  [  666.319429]  mptcp_userspace_pm_get_local_id+0x1dc/0x1f0\n  [  666.319433]  mptcp_pm_get_local_id+0x371/0x440\n  ...\n  [  666.319821] Allocated by task 45539:\n  [  666.319844]  kasan_save_stack+0x33/0x60\n  [  666.319855]  kasan_save_track+0x14/0x30\n  [  666.319858]  __kasan_kmalloc+0x8f/0xa0\n  [  666.319863]  __kmalloc_noprof+0x1e7/0x520\n  [  666.319867]  sock_kmalloc+0xdf/0x130\n  [  666.319885]  sock_kmemdup+0x1b/0x40\n  [  666.319888]  mptcp_userspace_pm_append_new_local_addr+0x261/0x500\n  [  666.319910]  mptcp_pm_nl_announce_doit+0x16a/0x610\n  ...\n  [  666.319967] Freed by task 45560:\n  [  666.319988]  kasan_save_stack+0x33/0x60\n  [  666.319991]  kasan_save_track+0x14/0x30\n  [  666.319994]  kasan_save_free_info+0x3b/0x60\n  [  666.319998]  __kasan_slab_free+0x43/0x70\n  [  666.320000]  kfree+0x166/0x440\n  [  666.320003]  sock_kfree_s+0x1d/0x50\n  [  666.320007]  mptcp_userspace_pm_delete_local_addr.isra.0+0x157/0x200\n  [  666.320011]  mptcp_pm_nl_subflow_destroy_doit+0x51d/0xea0\n\nFix by copying the id into a local variable while still holding the lock,\nand use -1 as a \"not found\" sentinel.","modified":"2026-08-31T05:26:27Z","published":"2026-08-10T13:20:03Z","upstream":["CVE-2026-68169"],"references":[{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-68169"}],"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-94859.json"}}],"schema_version":"1.9.0"}