Description
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->add_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:
<TASK>
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
</TASK>
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---
mptcp: fix a race in mptcp_pm_del_add_timer()
mptcp_pm_del_add_timer() can call sk_stop_timer_sync(sk, &entry->add_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:
<TASK>
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
</TASK>
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---
Analysis
Analysis and contextual insights are available on OpenCVE Cloud.
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | ||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Linux | Linux | unaffected |
|
||||||||||||||||||||||||||||||
| Linux | Linux | affected |
|
No data.
No data.
No data available yet.
Remediation
No vendor fix or workaround currently provided.
Additional remediation guidance may be available on OpenCVE Cloud.
Tracking
Sign in to view the affected projects.
Advisories
| Source | ID | Title |
|---|---|---|
 Debian DLA |
DLA-4404-1 | linux security update |
| Debian DLA |
DLA-4436-1 | linux-6.1 security update |
 Ubuntu USN |
USN-8094-1 | Linux kernel vulnerabilities |
| Ubuntu USN |
USN-8095-1 | Linux kernel vulnerabilities |
| Ubuntu USN |
USN-8096-1 | Linux kernel vulnerabilities |
| Ubuntu USN |
USN-8095-2 | Linux kernel (FIPS) vulnerabilities |
| Ubuntu USN |
USN-8096-2 | Linux kernel (FIPS) vulnerabilities |
| Ubuntu USN |
USN-8100-1 | Linux kernel (NVIDIA) vulnerabilities |
| Ubuntu USN |
USN-8094-2 | Linux kernel vulnerabilities |
| Ubuntu USN |
USN-8095-3 | Linux kernel (Real-time) vulnerabilities |
| Ubuntu USN |
USN-8096-3 | Linux kernel vulnerabilities |
| Ubuntu USN |
USN-8096-4 | Linux kernel (Real-time) vulnerabilities |
| Ubuntu USN |
USN-8095-4 | Linux kernel (AWS) vulnerabilities |
| Ubuntu USN |
USN-8096-5 | Linux kernel (NVIDIA Tegra IGX) vulnerabilities |
| Ubuntu USN |
USN-8116-1 | Linux kernel (Intel IoTG Real-time) vulnerabilities |
| Ubuntu USN |
USN-8094-3 | Linux kernel (Real-time) vulnerabilities |
| Ubuntu USN |
USN-8094-4 | Linux kernel (Azure) vulnerabilities |
| Ubuntu USN |
USN-8125-1 | Linux kernel (Azure) vulnerabilities |
| Ubuntu USN |
USN-8126-1 | Linux kernel (Azure) vulnerabilities |
| Ubuntu USN |
USN-8094-5 | Linux kernel (Raspberry Pi) vulnerabilities |
| Ubuntu USN |
USN-8095-5 | Linux kernel (Raspberry Pi) vulnerabilities |
| Ubuntu USN |
USN-8141-1 | Linux kernel (Raspberry Pi) vulnerabilities |
| Ubuntu USN |
USN-8152-1 | Linux kernel (OEM) vulnerabilities |
| Ubuntu USN |
USN-8163-1 | Linux kernel (Azure FIPS) vulnerabilities |
| Ubuntu USN |
USN-8165-1 | Linux kernel (Azure FIPS) vulnerabilities |
| Ubuntu USN |
USN-8163-2 | Linux kernel (Azure) vulnerabilities |
| Ubuntu USN |
USN-8243-1 | Linux kernel (Azure) vulnerabilities |
| Ubuntu USN |
USN-8261-1 | Linux kernel (Xilinx) vulnerabilities |
References
History
Wed, 17 Dec 2025 00:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| References |
| |
| Metrics |
threat_severity
|
cvssV3_1
|
Sat, 06 Dec 2025 21:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| References |
|
Thu, 04 Dec 2025 16:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | 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->add_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: <TASK> 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 </TASK> 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--- | |
| Title | mptcp: fix a race in mptcp_pm_del_add_timer() | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
MITRE
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-05-11T21:45:50.143Z
Reserved: 2025-04-16T07:20:57.182Z
Link: CVE-2025-40257
Vulnrichment
No data.
NVD
Status : Deferred
Published: 2025-12-04T16:16:19.503
Modified: 2026-04-15T00:35:42.020
Link: CVE-2025-40257
Redhat
OpenCVE Enrichment
No data.
Weaknesses
No weakness.