CVE-2025-40281

CVE-2025-40281 is a security vulnerability that is still awaiting full analysis and scoring. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

Description

In the Linux kernel, the following vulnerability has been resolved: sctp: prevent possible shift-out-of-bounds in sctp_transport_update_rto syzbot reported a possible shift-out-of-bounds [1] Blamed commit added rto_alpha_max and rto_beta_max set to 1000. It is unclear if some sctp users are setting very large rto_alpha and/or rto_beta. In order to prevent user regression, perform the test at run time. Also add READ_ONCE() annotations as sysctl values can change under us. [1] UBSAN: shift-out-of-bounds in net/sctp/transport.c:509:41 shift exponent 64 is too large for 32-bit type 'unsigned int' CPU: 0 UID: 0 PID: 16704 Comm: syz.2.2320 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 Call Trace: <TASK> __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x16c/0x1f0 lib/dump_stack.c:120 ubsan_epilogue lib/ubsan.c:233 [inline] __ubsan_handle_shift_out_of_bounds+0x27f/0x420 lib/ubsan.c:494 sctp_transport_update_rto.cold+0x1c/0x34b net/sctp/transport.c:509 sctp_check_transmitted+0x11c4/0x1c30 net/sctp/outqueue.c:1502 sctp_outq_sack+0x4ef/0x1b20 net/sctp/outqueue.c:1338 sctp_cmd_process_sack net/sctp/sm_sideeffect.c:840 [inline] sctp_cmd_interpreter net/sctp/sm_sideeffect.c:1372 [inline]

Frequently asked questions

What is CVE-2025-40281?
In the Linux kernel, the following vulnerability has been resolved: sctp: prevent possible shift-out-of-bounds in sctp_transport_update_rto syzbot reported a possible shift-out-of-bounds [1] Blamed commit added rto_alpha_max and rto_beta_max set to 1000. It is unclear if some sctp users are setting very large rto_alpha and/or rto_beta. In order to prevent user regression, perform the test at run time. Also add READ_ONCE() annotations as sysctl values can change under us. [1] UBSAN: shift-out-of-bounds in net/sctp/transport.c:509:41 shift exponent 64 is too large for 32-bit type 'unsigned int' CPU: 0 UID: 0 PID: 16704 Comm: syz.2.2320 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 Call Trace: <TASK> __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x16c/0x1f0 lib/dump_stack.c:120 ubsan_epilogue lib/ubsan.c:233 [inline] __ubsan_handle_shift_out_of_bounds+0x27f/0x420 lib/ubsan.c:494 sctp_transport_update_rto.cold+0x1c/0x34b net/sctp/transport.c:509 sctp_check_transmitted+0x11c4/0x1c30 net/sctp/outqueue.c:1502 sctp_outq_sack+0x4ef/0x1b20 net/sctp/outqueue.c:1338 sctp_cmd_process_sack net/sctp/sm_sideeffect.c:840 [inline] sctp_cmd_interpreter net/sctp/sm_sideeffect.c:1372 [inline]
Is CVE-2025-40281 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (9th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2025-40281?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2025-40281 have an EU (EUVD) identifier?
Yes. CVE-2025-40281 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-201574.
When was CVE-2025-40281 published?
CVE-2025-40281 was published on 2025-12-06 and last updated on 2026-06-17.

References