Highly exploitable, CVE-2025-68785 poses a critical security risk that could lead to severe breaches.
Status: Deferred
Last updated: 🕕 30 Jul 2026, 06:24 UTC
Originally published on: 🕓 13 Jan 2026, 16:15 UTC
Time between publication and last update: 197 days
CVSS Release: version 3
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Secondary
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
CVE-2025-68785: In the Linux kernel, the following vulnerability has been resolved: net: openvswitch: fix middle attribute validation in push_nsh() action The push_nsh() action structure looks like this: OVS_ACTION_ATTR_PUSH_NSH(OVS_KEY_ATTR_NSH(OVS_NSH_KEY_ATTR_BASE,...)) The outermost OVS_ACTION_ATTR_PUSH_NSH attribute is OK'ed by the nla_for_each_nested() inside __ovs_nla_copy_actions(). The innermost OVS_NSH_KEY_ATTR_BASE/MD1/MD2 are OK'ed by the nla_for_each_nested() inside nsh_key_put_from_nlattr(). But nothing checks if the attribute in the middle is OK. We don't even check that this attribute is the OVS_KEY_ATTR_NSH. We just do a double unwrap with a pair of nla_data() calls - first time directly while calling validate_push_nsh() and the second time as part of the nla_for_each_nested() macro, which isn't safe, potentially causing invalid memory access if the size of this attribute is incorrect. The failure may not be noticed during validation due to larger netlink buffer, but cause trouble later during action execution where the buffer is allocated exactly to the size: BUG: KASAN: slab-out-of-bounds in nsh_hdr_from_nlattr+0x1dd/0x6a0 [openvswitch] Read of size 184 at addr ffff88816459a634 by task a.out/22624 CPU: 8 UID: 0 PID: 22624 6.18.0-rc7+ #115 PREEMPT(voluntary) Call Trace: <TASK> dump_stack_lvl+0x51/0x70 print_address_description.constprop.0+0x2c/0x390 kasan_report+0xdd/0x110 kasan_check_range+0x35/0x1b0 __asan_memcpy+0x20/0x60 nsh_hdr_from_nlattr+0x1dd/0x6a0 [openvswitch] push_nsh+0x82/0x120 [openvswitch] do_execute_actions+0x1405/0x2840 [openvswitch] ovs_execute_actions+0xd5/0x3b0 [openvswitch] ovs_packet_cmd_execute+0x949/0xdb0 [openvswitch] genl_family_rcv_msg_doit+0x1d6/0x2b0 genl_family_rcv_msg+0x336/0x580 genl_rcv_msg+0x9f/0x130 netlink_rcv_skb+0x11f/0x370 genl_rcv+0x24/0x40 netlink_unicast+0x73e/0xaa0 netlink_sendmsg+0x744/0xbf0 __sys_sendto+0x3d6/0x450 do_syscall_64+0x79/0x2c0 entry_SYSCALL_64_after_hwframe+0x76/0x7e </TASK> Let's add some checks that the attribute is properly sized and it's the only one attribute inside the action. Technically, there is no real reason for OVS_KEY_ATTR_NSH to be there, as we know that we're pushing an NSH header already, it just creates extra nesting, but that's how uAPI works today. So, keeping as it is.
The exploitability of CVE-2025-68785 depends on two key factors: attack complexity (the level of effort required to execute an exploit) and privileges required (the access level an attacker needs).
CVE-2025-68785 presents an accessible attack vector with minimal effort required. Restricting access controls and implementing security updates are critical to reducing exploitation risks.
A lower complexity and fewer privilege requirements make exploitation easier. Security teams should evaluate these aspects to determine the urgency of mitigation strategies, such as patch management and access control policies.
Attack Complexity (AC) measures the difficulty in executing an exploit. A high AC means that specific conditions must be met, making an attack more challenging, while a low AC means the vulnerability can be exploited with minimal effort.
Privileges Required (PR) determine the level of system access necessary for an attack. Vulnerabilities requiring no privileges are more accessible to attackers, whereas high privilege requirements limit exploitation to authorized users with elevated access.
Above is the CVSS Sub-score Breakdown for CVE-2025-68785, illustrating how Base, Impact, and Exploitability factors combine to form the overall severity rating. A higher sub-score typically indicates a more severe or easier-to-exploit vulnerability.
Below is the Impact Analysis for CVE-2025-68785, showing how Confidentiality, Integrity, and Availability might be affected if the vulnerability is exploited. Higher values usually signal greater potential damage.
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