CVE-2025-38146 net: openvswitch: Fix the dead loop of MPLS parse
A remote attacker can cause a denial of service via a dead loop in the Linux kernel's Open vSwitch MPLS parser.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-38146?
CVE-2025-38146 is a critical denial of service vulnerability in Debian Debian Linux, published on 3 Jul 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
net: openvswitch: Fix the dead loop of MPLS parse
The unexpected MPLS packet may not end with the bottom label stack. When there are many stacks, The label count value has wrapped around. A dead loop occurs, soft lockup/CPU stuck finally.
stack backtrace: UBSAN: array-index-out-of-bounds in /build/linux-0Pa0xK/linux-5.15.0/net/openvswitch/flow.c:662:26 index -1 is out of range for type '__be32 [3]' CPU: 34 PID: 0 Comm: swapper/34 Kdump: loaded Tainted: G OE 5.15.0-121-generic #131-Ubuntu Hardware name: Dell Inc. PowerEdge C6420/0JP9TF, BIOS 2.12.2 07/14/2021 Call Trace: <IRQ> show_stack+0x52/0x5c dump_stack_lvl+0x4a/0x63 dump_stack+0x10/0x16 ubsan_epilogue+0x9/0x36 __ubsan_handle_out_of_bounds.cold+0x44/0x49 key_extract_l3l4+0x82a/0x840 [openvswitch] ? kfree_skbmem+0x52/0xa0 key_extract+0x9c/0x2b0 [openvswitch] ovs_flow_key_extract+0x124/0x350 [openvswitch] ovs_vport_receive+0x61/0xd0 [openvswitch] ? kernel_init_free_pages.part.0+0x4a/0x70 ? get_page_from_freelist+0x353/0x540 netdev_port_receive+0xc4/0x180 [openvswitch] ? netdev_port_receive+0x180/0x180 [openvswitch] netdev_frame_hook+0x1f/0x40 [openvswitch] __netif_receive_skb_core.constprop.0+0x23a/0xf00 __netif_receive_skb_list_core+0xfa/0x240 netif_receive_skb_list_internal+0x18e/0x2a0 napi_complete_done+0x7a/0x1c0 bnxt_poll+0x155/0x1c0 [bnxt_en] __napi_poll+0x30/0x180 net_rx_action+0x126/0x280 ? bnxt_msix+0x67/0x80 [bnxt_en] handle_softirqs+0xda/0x2d0 irq_exit_rcu+0x96/0xc0 common_interrupt+0x8e/0xa0 </IRQ>
Weakness: CWE-129
Which versions are affected by CVE-2025-38146?
It affects 2 products.
Products include Debian Debian Linux, Linux kernel.
How do I fix CVE-2025-38146?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2025-38146 being exploited?
There is no known exploitation of CVE-2025-38146 in the wild and no public exploit code.
Other vulnerabilities in Debian Debian Linux
Sources
Also known as AZL-64487, BELL-CVE-2025-38146, DEBIAN-CVE-2025-38146, GHSA-28ww-ch52-w98x, ROOT-OS-DEBIAN-11-CVE-2025-38146, ROOT-OS-DEBIAN-12-CVE-2025-38146 and 3 more.