ZDI-26-688: Linux Kernel OpenvSwitch Race Condition Local Privilege Escalation Vulnerability
ZDI discloses Linux Kernel Open vSwitch race condition (CVE-2026-74465) allowing low-privileged local attackers to escalate privileges, CVSS 7.8.
ZDI-26-688 describes a race condition local privilege escalation vulnerability in the Linux Kernel's Open vSwitch implementation, tracked as CVE-2026-74465 with a CVSS rating of 7.8. An attacker must first obtain the ability to execute low-privileged code on the target system. Successful exploitation grants elevated privileges on affected installations.
- CVE-2026-74465, CVSS 7.8, Linux Kernel Open vSwitch
- Local privilege escalation via race condition
- Requires only prior low-privileged code execution
Vulnerabilities mentionedAll →
| CVE | Vulnerability | CVSS | EPSS | Flags | Affected | Exposure | Published |
|---|---|---|---|---|---|---|---|
| CVE-2026-74465 | In the Linux kernel, the following vulnerability has been resolved: In the Linux kernel, the following vulnerability has been resolved: net: openvswitch: fix potential UAF on meter attach failure While attaching a newly created meter attach_meter() function makes the new meter visible to other CPUs but can still fail afterwards. On failure, it detaches the meter back and returns an error. However, this is an unexpected behavior for the ovs_meter_cmd_set() that uses a plain kfree(meter) on attach failure without waiting for RCU readers to stop using it, assuming it was never visible. This is never a problem for ovs-vswitchd as it always creates meters before creating any flows that use them. But the UAF can be triggered with a custom application using uAPI: BUG: KASAN: slab-use-after-free in ovs_meter_execute (net/openvswitch/meter.c:653) Read of size 8 at addr ffff88810d152650 by task meter/2508 Call Trace: ovs_meter_execute (net/openvswitch/meter.c:653) do_execute_actions (net/openvswitch/actions.c:1407) ovs_execute_actions (net/openvswitch/actions.c:1584) ovs_packet_cmd_execute (net/openvswitch/datapath.c:703) ... netlink_sendmsg (af_netlink.c:1900) Allocated by task 2519: __kasan_kmalloc (mm/kasan/common.c:398 mm/kasan/common.c:415) ovs_meter_cmd_set (net/openvswitch/meter.c:422) ... netlink_sendmsg (af_netlink.c:1900) Freed by task 2519: kfree (mm/slub.c:2705 mm/slub.c:6405 mm/slub.c:6720) ovs_meter_cmd_set (net/openvswitch/meter.c:479) ... netlink_sendmsg (af_netlink.c:1900) Fix that by making sure attach_meter() doesn't make the meter visible until all the checks are done and the function can't fail anymore. This also makes sure the "hash" value is calculated after the potential re-sizing of the table. Reported by Trend Micro's Zero Day Initiative as ZDI-CAN-31642. NVD description · AI analysis pending | 7.8 | <1% | — | — |
This vulnerability allows local attackers to escalate privileges on affected installations of Linux Kernel. An attacker must first obtain the ability to execute low-privileged code on the target system in order to exploit this vulnerability. The ZDI has assigned a CVSS rating of 7.8. The following CVEs are assigned: CVE-2026-74465.
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