{"id":"DEBIAN-CVE-2025-40257","details":"In the Linux kernel, the following vulnerability has been resolved:  mptcp: fix a race in mptcp_pm_del_add_timer()  mptcp_pm_del_add_timer() can call sk_stop_timer_sync(sk, &entry-\u003eadd_timer) while another might have free entry already, as reported by syzbot.  Add RCU protection to fix this issue.  Also change confusing add_timer variable with stop_timer boolean.  syzbot report:  BUG: KASAN: slab-use-after-free in __timer_delete_sync+0x372/0x3f0 kernel/time/timer.c:1616 Read of size 4 at addr ffff8880311e4150 by task kworker/1:1/44  CPU: 1 UID: 0 PID: 44 Comm: kworker/1:1 Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 Workqueue: events mptcp_worker Call Trace:  \u003cTASK\u003e   dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120   print_address_description mm/kasan/report.c:378 [inline]   print_report+0xca/0x240 mm/kasan/report.c:482   kasan_report+0x118/0x150 mm/kasan/report.c:595   __timer_delete_sync+0x372/0x3f0 kernel/time/timer.c:1616   sk_stop_timer_sync+0x1b/0x90 net/core/sock.c:3631   mptcp_pm_del_add_timer+0x283/0x310 net/mptcp/pm.c:362   mptcp_incoming_options+0x1357/0x1f60 net/mptcp/options.c:1174   tcp_data_queue+0xca/0x6450 net/ipv4/tcp_input.c:5361   tcp_rcv_established+0x1335/0x2670 net/ipv4/tcp_input.c:6441   tcp_v4_do_rcv+0x98b/0xbf0 net/ipv4/tcp_ipv4.c:1931   tcp_v4_rcv+0x252a/0x2dc0 net/ipv4/tcp_ipv4.c:2374   ip_protocol_deliver_rcu+0x221/0x440 net/ipv4/ip_input.c:205   ip_local_deliver_finish+0x3bb/0x6f0 net/ipv4/ip_input.c:239   NF_HOOK+0x30c/0x3a0 include/linux/netfilter.h:318   NF_HOOK+0x30c/0x3a0 include/linux/netfilter.h:318   __netif_receive_skb_one_core net/core/dev.c:6079 [inline]   __netif_receive_skb+0x143/0x380 net/core/dev.c:6192   process_backlog+0x31e/0x900 net/core/dev.c:6544   __napi_poll+0xb6/0x540 net/core/dev.c:7594   napi_poll net/core/dev.c:7657 [inline]   net_rx_action+0x5f7/0xda0 net/core/dev.c:7784   handle_softirqs+0x22f/0x710 kernel/softirq.c:622   __do_softirq kernel/softirq.c:656 [inline]   __local_bh_enable_ip+0x1a0/0x2e0 kernel/softirq.c:302   mptcp_pm_send_ack net/mptcp/pm.c:210 [inline]  mptcp_pm_addr_send_ack+0x41f/0x500 net/mptcp/pm.c:-1   mptcp_pm_worker+0x174/0x320 net/mptcp/pm.c:1002   mptcp_worker+0xd5/0x1170 net/mptcp/protocol.c:2762   process_one_work kernel/workqueue.c:3263 [inline]   process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3346   worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427   kthread+0x711/0x8a0 kernel/kthread.c:463   ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158   ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245  \u003c/TASK\u003e  Allocated by task 44:   kasan_save_stack mm/kasan/common.c:56 [inline]   kasan_save_track+0x3e/0x80 mm/kasan/common.c:77   poison_kmalloc_redzone mm/kasan/common.c:400 [inline]   __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:417   kasan_kmalloc include/linux/kasan.h:262 [inline]   __kmalloc_cache_noprof+0x1ef/0x6c0 mm/slub.c:5748   kmalloc_noprof include/linux/slab.h:957 [inline]   mptcp_pm_alloc_anno_list+0x104/0x460 net/mptcp/pm.c:385   mptcp_pm_create_subflow_or_signal_addr+0xf9d/0x1360 net/mptcp/pm_kernel.c:355   mptcp_pm_nl_fully_established net/mptcp/pm_kernel.c:409 [inline]   __mptcp_pm_kernel_worker+0x417/0x1ef0 net/mptcp/pm_kernel.c:1529   mptcp_pm_worker+0x1ee/0x320 net/mptcp/pm.c:1008   mptcp_worker+0xd5/0x1170 net/mptcp/protocol.c:2762   process_one_work kernel/workqueue.c:3263 [inline]   process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3346   worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427   kthread+0x711/0x8a0 kernel/kthread.c:463   ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158   ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245  Freed by task 6630:   kasan_save_stack mm/kasan/common.c:56 [inline]   kasan_save_track+0x3e/0x80 mm/kasan/common.c:77   __kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:587   kasan_save_free_info mm/kasan/kasan.h:406 [inline]   poison_slab_object m ---truncated---","modified":"2026-09-01T16:06:17.271218193Z","published":"2025-12-04T16:16:19.503Z","upstream":["CVE-2025-40257"],"references":[{"type":"ADVISORY","url":"https://security-tracker.debian.org/tracker/CVE-2025-40257"}],"affected":[{"package":{"name":"linux","ecosystem":"Debian:12","purl":"pkg:deb/debian/linux?arch=source&distro=bookworm"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.1.159-1"}]}],"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","6.1.27-1","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 yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2025-40257.json"}},{"package":{"name":"linux","ecosystem":"Debian:13","purl":"pkg:deb/debian/linux?arch=source&distro=trixie"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.12.63-1"}]}],"versions":["6.12.38-1","6.12.41-1","6.12.43-1","6.12.43-1~bpo12+1","6.12.48-1","6.12.57-1","6.12.57-1~bpo12+1","6.12.63-1~bpo12+1"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2025-40257.json"}},{"package":{"name":"linux","ecosystem":"Debian:14","purl":"pkg:deb/debian/linux?arch=source&distro=forky"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.17.10-1"}]}],"versions":["6.12.100-1","6.12.101-1","6.12.105-1","6.12.107-1","6.12.38-1","6.12.41-1","6.12.43-1","6.12.43-1~bpo12+1","6.12.48-1","6.12.57-1","6.12.57-1~bpo12+1","6.12.63-1","6.12.63-1~bpo12+1","6.12.69-1","6.12.69-1~bpo12+1","6.12.73-1","6.12.73-1~bpo12+1","6.12.74-1","6.12.74-2","6.12.74-2~bpo12+1","6.12.85-1","6.12.85-1~bpo12+1","6.12.86-1","6.12.86-1~bpo12+1","6.12.88-1","6.12.88-1~bpo12+1","6.12.90-1","6.12.90-1~bpo12+1","6.12.90-2","6.12.90-2~bpo12+1","6.12.94-1","6.12.94-1~bpo12+1","6.12.95-1","6.12.95-1~bpo12+1","6.12.96-1","6.13.10-1~exp1","6.13.11-1~exp1","6.13.2-1~exp1","6.13.3-1~exp1","6.13.4-1~exp1","6.13.5-1~exp1","6.13.6-1~exp1","6.13.7-1~exp1","6.13.8-1~exp1","6.13.9-1~exp1","6.13~rc6-1~exp1","6.13~rc7-1~exp1","6.14.3-1~exp1","6.14.5-1~exp1","6.14.6-1~exp1","6.15-1~exp1","6.15.1-1~exp1","6.15.2-1~exp1","6.15.3-1~exp1","6.15.4-1~exp1","6.15.5-1~exp1","6.15.6-1~exp1","6.15~rc7-1~exp1","6.16-1~exp1","6.16.1-1~exp1","6.16.10-1","6.16.11-1","6.16.12-1","6.16.12-1~bpo13+1","6.16.12-2","6.16.3-1","6.16.3-1~bpo13+1","6.16.5-1","6.16.6-1","6.16.7-1","6.16.8-1","6.16.9-1","6.16~rc7-1~exp1","6.17.2-1~exp1","6.17.5-1~exp1","6.17.6-1","6.17.7-1","6.17.7-2","6.17.8-1","6.17.8-1~bpo13+1","6.17.9-1"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2025-40257.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"}]}