CVE-2025-21653net_sched: cls_flow: validate TCA_FLOW_RSHIFT attribute
Updated under an hour ago ()
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No exploitation reported and no EPSS estimate yet.
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In the Linux kernel, the following vulnerability has been resolved: net_sched: cls_flow: validate TCA_FLOW_RSHIFT attribute syzbot found that TCA_FLOW_RSHIFT attribute was not validated. Right shitfing a 32bit integer is undefined for large shift values. UBSAN: shift-out-of-bounds in net/sched/cls_flow.c:329:23 shift exponent 9445 is too large for 32-bit type 'u32' (aka 'unsigned int') CPU: 1 UID: 0 PID: 54 Comm: kworker/u8:3 Not tainted 6.13.0-rc3-syzkaller-00180-g4f619d518db9 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 Workqueue: ipv6_addrconf addrconf_dad_work Call Trace: <TASK> __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120 ubsan_epilogue lib/ubsan.c:231 [inline] __ubsan_handle_shift_out_of_bounds+0x3c8/0x420 lib/ubsan.c:468 flow_classify+0x24d5/0x25b0 net/sched/cls_flow.c:329 tc_classify include/net/tc_wrapper.h:197 [inline] __tcf_classify net/sched/cls_api.c:1771 [inline] tcf_classify+0x420/0x1160 net/sched/cls_api.c:1867 sfb_classify net/sched/sch_sfb.c:260 [inline] sfb_enqueue+0x3ad/0x18b0 net/sched/sch_sfb.c:318 dev_qdisc_enqueue+0x4b/0x290 net/core/dev.c:3793 __dev_xmit_skb net/core/dev.c:3889 [inline] __dev_queue_xmit+0xf0e/0x3f50 net/core/dev.c:4400 dev_queue_xmit include/linux/netdevice.h:3168 [inline] neigh_hh_output include/net/neighbour.h:523 [inline] neigh_output include/net/neighbour.h:537 [inline] ip_finish_output2+0xd41/0x1390 net/ipv4/ip_output.c:236 iptunnel_xmit+0x55d/0x9b0 net/ipv4/ip_tunnel_core.c:82 udp_tunnel_xmit_skb+0x262/0x3b0 net/ipv4/udp_tunnel_core.c:173 geneve_xmit_skb drivers/net/geneve.c:916 [inline] geneve_xmit+0x21dc/0x2d00 drivers/net/geneve.c:1039 __netdev_start_xmit include/linux/netdevice.h:5002 [inline] netdev_start_xmit include/linux/netdevice.h:5011 [inline] xmit_one net/core/dev.c:3590 [inline] dev_hard_start_xmit+0x27a/0x7d0 net/core/dev.c:3606 __dev_queue_xmit+0x1b73/0x3f50 net/core/dev.c:4434
- CVSS
- Not yet scored
- Weakness (CWE)
- Not given
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Linux
- NVD analysis
- Not yet received
- Record last updated
- Oct 15, 2026
- First seen by InfoSec Signals
- Oct 15, 2026
Affected products
Linux Linux linux:linux (from the name) | from e5dfb815181fcb186d6080ac3a091eadff2d98fe before 9858f4afeb2e59506e714176bd3e135539a3eeec; from e5dfb815181fcb186d6080ac3a091eadff2d98fe before 43658e4a5f2770ad94e93362885ff51c10cf3179; from e5dfb815181fcb186d6080ac3a091eadff2d98fe before a313d6e6d5f3a631cae5a241c392c28868aa5c5e; from e5dfb815181fcb186d6080ac3a091eadff2d98fe before 2011749ca96460386844dfc7e0fde53ebee96f3c; from e5dfb815181fcb186d6080ac3a091eadff2d98fe before e54beb9aed2a90dddf4c5d68fcfc9a01f3e40a61; from e5dfb815181fcb186d6080ac3a091eadff2d98fe before 6fde663f7321418996645ee602a473457640542f; from e5dfb815181fcb186d6080ac3a091eadff2d98fe before a039e54397c6a75b713b9ce7894a62e06956aa92 | CNA record |
Siemens SIMATIC S7-1500 TM MFP - BIOS siemens:simatic_s7_1500_tm_mfp_bios (from the name) | all versions | CISA ADP |
Siemens SIMATIC S7-1500 TM MFP - GNU/Linux subsystem siemens:simatic_s7_1500_tm_mfp_gnu_linux_subsystem (from the name) | all versions | CISA ADP |
References
- https://git.kernel.org/stable/c/9858f4afeb2e59506e714176bd3e135539a3eeec
- https://git.kernel.org/stable/c/43658e4a5f2770ad94e93362885ff51c10cf3179
- https://git.kernel.org/stable/c/a313d6e6d5f3a631cae5a241c392c28868aa5c5e
- https://git.kernel.org/stable/c/2011749ca96460386844dfc7e0fde53ebee96f3c
- https://git.kernel.org/stable/c/e54beb9aed2a90dddf4c5d68fcfc9a01f3e40a61
- https://git.kernel.org/stable/c/6fde663f7321418996645ee602a473457640542f
- https://git.kernel.org/stable/c/a039e54397c6a75b713b9ce7894a62e06956aa92
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.