{"id":"DEBIAN-CVE-2026-68169","details":"In the Linux kernel, the following vulnerability has been resolved:  mptcp: pm: userspace: fix use-after-free in get_local_id  In mptcp_pm_userspace_get_local_id(), the address entry is looked up under spinlock, but its id is read after dropping the lock. A concurrent deletion can free the entry between the unlock and the read, leading to UAF.  The race window is narrow. It was reproduced only with a locally constructed stress test that repeatedly overlaps an MP_JOIN SYN with a MPTCP_PM_CMD_SUBFLOW_DESTROY request.  However, the KASAN report below confirms that the race is reachable:    [  666.319376] BUG: KASAN: slab-use-after-free in mptcp_userspace_pm_get_local_id+0x1dc/0x1f0   [  666.319386] Read of size 1 at addr ffff888124845610 by task swapper/0/0   ...   [  666.319401] Call Trace:   [  666.319405]  \u003cIRQ\u003e   [  666.319408]  dump_stack_lvl+0x53/0x70   [  666.319412]  print_address_description.constprop.0+0x2c/0x3b0   [  666.319418]  print_report+0xbe/0x2b0   [  666.319421]  ? mptcp_userspace_pm_get_local_id+0x1dc/0x1f0   [  666.319423]  kasan_report+0xce/0x100   [  666.319426]  ? mptcp_userspace_pm_get_local_id+0x1dc/0x1f0   [  666.319429]  mptcp_userspace_pm_get_local_id+0x1dc/0x1f0   [  666.319433]  mptcp_pm_get_local_id+0x371/0x440   ...   [  666.319821] Allocated by task 45539:   [  666.319844]  kasan_save_stack+0x33/0x60   [  666.319855]  kasan_save_track+0x14/0x30   [  666.319858]  __kasan_kmalloc+0x8f/0xa0   [  666.319863]  __kmalloc_noprof+0x1e7/0x520   [  666.319867]  sock_kmalloc+0xdf/0x130   [  666.319885]  sock_kmemdup+0x1b/0x40   [  666.319888]  mptcp_userspace_pm_append_new_local_addr+0x261/0x500   [  666.319910]  mptcp_pm_nl_announce_doit+0x16a/0x610   ...   [  666.319967] Freed by task 45560:   [  666.319988]  kasan_save_stack+0x33/0x60   [  666.319991]  kasan_save_track+0x14/0x30   [  666.319994]  kasan_save_free_info+0x3b/0x60   [  666.319998]  __kasan_slab_free+0x43/0x70   [  666.320000]  kfree+0x166/0x440   [  666.320003]  sock_kfree_s+0x1d/0x50   [  666.320007]  mptcp_userspace_pm_delete_local_addr.isra.0+0x157/0x200   [  666.320011]  mptcp_pm_nl_subflow_destroy_doit+0x51d/0xea0  Fix by copying the id into a local variable while still holding the lock, and use -1 as a \"not found\" sentinel.","modified":"2026-09-19T22:01:55.267906417Z","published":"2026-08-10T13:20:03.483Z","upstream":["CVE-2026-68169"],"references":[{"type":"ADVISORY","url":"https://security-tracker.debian.org/tracker/CVE-2026-68169"}],"affected":[{"package":{"name":"linux","ecosystem":"Debian:12","purl":"pkg:deb/debian/linux?arch=source&distro=bookworm"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.1.187-1"}]}],"versions":["6.1.106-1","6.1.106-2","6.1.106-3","6.1.112-1","6.1.115-1","6.1.119-1","6.1.123-1","6.1.124-1","6.1.128-1","6.1.129-1","6.1.133-1","6.1.135-1","6.1.137-1","6.1.139-1","6.1.140-1","6.1.147-1","6.1.148-1","6.1.153-1","6.1.158-1","6.1.159-1","6.1.162-1","6.1.164-1","6.1.170-1","6.1.170-2","6.1.170-3","6.1.172-1","6.1.174-1","6.1.176-1","6.1.177-1","6.1.180-1","6.1.27-1","6.1.37-1","6.1.38-1","6.1.38-2","6.1.38-2~bpo11+1","6.1.38-3","6.1.38-4","6.1.38-4~bpo11+1","6.1.52-1","6.1.55-1","6.1.55-1~bpo11+1","6.1.64-1","6.1.66-1","6.1.67-1","6.1.69-1","6.1.69-1~bpo11+1","6.1.76-1","6.1.76-1~bpo11+1","6.1.82-1","6.1.85-1","6.1.90-1","6.1.90-1~bpo11+1","6.1.94-1","6.1.94-1~bpo11+1","6.1.98-1","6.1.99-1"],"ecosystem_specific":{"urgency":"not 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