mptcp: fix race condition in mptcp_schedule_work()

Summary

CVECVE-2025-40258
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2025-12-04 16:16:19 UTC
Updated2026-06-02 14:16:32 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: mptcp: fix race condition in mptcp_schedule_work() syzbot reported use-after-free in mptcp_schedule_work() [1] Issue here is that mptcp_schedule_work() schedules a work, then gets a refcount on sk->sk_refcnt if the work was scheduled. This refcount will be released by mptcp_worker(). [A] if (schedule_work(...)) { [B] sock_hold(sk); return true; } Problem is that mptcp_worker() can run immediately and complete before [B] We need instead : sock_hold(sk); if (schedule_work(...)) return true; sock_put(sk); [1] refcount_t: addition on 0; use-after-free. WARNING: CPU: 1 PID: 29 at lib/refcount.c:25 refcount_warn_saturate+0xfa/0x1d0 lib/refcount.c:25 Call Trace: <TASK> __refcount_add include/linux/refcount.h:-1 [inline] __refcount_inc include/linux/refcount.h:366 [inline] refcount_inc include/linux/refcount.h:383 [inline] sock_hold include/net/sock.h:816 [inline] mptcp_schedule_work+0x164/0x1a0 net/mptcp/protocol.c:943 mptcp_tout_timer+0x21/0xa0 net/mptcp/protocol.c:2316 call_timer_fn+0x17e/0x5f0 kernel/time/timer.c:1747 expire_timers kernel/time/timer.c:1798 [inline] __run_timers kernel/time/timer.c:2372 [inline] __run_timer_base+0x648/0x970 kernel/time/timer.c:2384 run_timer_base kernel/time/timer.c:2393 [inline] run_timer_softirq+0xb7/0x180 kernel/time/timer.c:2403 handle_softirqs+0x22f/0x710 kernel/softirq.c:622 __do_softirq kernel/softirq.c:656 [inline] run_ktimerd+0xcf/0x190 kernel/softirq.c:1138 smpboot_thread_fn+0x542/0xa60 kernel/smpboot.c:160 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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected 3b1d6210a9577369103330b0d802b0bf74b65e7f f865e6595acf33083168db76921e66ace8bf0e5b git Not specified
CNA Linux Linux affected 3b1d6210a9577369103330b0d802b0bf74b65e7f 99908e2d601236842d705d5fd04fb349577316f5 git Not specified
CNA Linux Linux affected 3b1d6210a9577369103330b0d802b0bf74b65e7f db4f7968a75250ca6c4ed70d0a78beabb2dcee18 git Not specified
CNA Linux Linux affected 3b1d6210a9577369103330b0d802b0bf74b65e7f 8f9ba1a99a89feef9b5867c15a0141a97e893309 git Not specified
CNA Linux Linux affected 3b1d6210a9577369103330b0d802b0bf74b65e7f ac28dfddedf6f209190950fc71bcff65ec4ab47b git Not specified
CNA Linux Linux affected 3b1d6210a9577369103330b0d802b0bf74b65e7f 3fc7723ed01d1130d4bf7063c50e0af60ecccbb4 git Not specified
CNA Linux Linux affected 3b1d6210a9577369103330b0d802b0bf74b65e7f 035bca3f017ee9dea3a5a756e77a6f7138cc6eea git Not specified
CNA Linux Linux affected 5.7 Not specified
CNA Linux Linux unaffected 5.7 semver Not specified
CNA Linux Linux unaffected 5.10.247 5.10.* semver Not specified
CNA Linux Linux unaffected 5.15.197 5.15.* semver Not specified
CNA Linux Linux unaffected 6.1.159 6.1.* semver Not specified
CNA Linux Linux unaffected 6.6.118 6.6.* semver Not specified
CNA Linux Linux unaffected 6.12.60 6.12.* semver Not specified
CNA Linux Linux unaffected 6.17.10 6.17.* semver Not specified
CNA Linux Linux unaffected 6.18 * original_commit_for_fix Not specified
ADP Siemens RUGGEDCOM RST2428P affected V4.0 custom Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/8f9ba1a99a89feef9b5867c15a0141a97e893309 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/99908e2d601236842d705d5fd04fb349577316f5 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/035bca3f017ee9dea3a5a756e77a6f7138cc6eea 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/f865e6595acf33083168db76921e66ace8bf0e5b 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/ac28dfddedf6f209190950fc71bcff65ec4ab47b 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/3fc7723ed01d1130d4bf7063c50e0af60ecccbb4 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
cert-portal.siemens.com/productcert/html/ssa-253495.html 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e cert-portal.siemens.com
git.kernel.org/stable/c/db4f7968a75250ca6c4ed70d0a78beabb2dcee18 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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