high 7.8

CVE-2026-74465 json

net: openvswitch: fix potential UAF on meter attach failure

published 2026-08-15 2 mo ago modified 2026-10-16 23 d ago also EUVD-2026-59658

cvss: 7.8; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.2%; EPSS 0.2% chance of exploitation in 30 days, percentile 4%
public exploits: 0; none known

In the Linux kernel, the following vulnerability has been resolved:

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.

Patch / fix

fixed in 1 distros 5 links 8

Linux Linux 5.10.265, 5.15.216, 6.1.183, 6.6.151, 6.12.103, 6.18.44, 7.1.8, 7.2

debian ubuntu suse opensuse azure linux

linux Debian 12 6.1.187-1
linux Debian 13 6.12.105-1
linux Debian 14 7.1.8-1
linux-6.12 Debian 12 6.12.107-1~deb12u1

debian advisories DEBIAN-CVE-2026-74465

linux Ubuntu 22.04 LTS 5.15.0-198.208
linux Ubuntu 26.04 LTS 7.0.0-42.42
linux-aws Ubuntu 22.04 LTS 5.15.0-1117.124
linux-aws Ubuntu 26.04 LTS 7.0.0-1016.17
linux-gcp Ubuntu 22.04 LTS 5.15.0-1118.128
linux-gcp Ubuntu 26.04 LTS 7.0.0-1016.18
linux-gke Ubuntu 22.04 LTS 5.15.0-1113.119
linux-ibm Ubuntu 22.04 LTS 5.15.0-1111.115

ubuntu advisories UBUNTU-CVE-2026-74465

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

kernel-64kb SLE Module for Basesystem 15 SP7 6.4.0-150700.53.84.1
kernel-syms SLE Module for Development Tools 15 SP7 6.4.0-150700.53.84.1
kernel-azure SLE Module for Public Cloud 15 SP7 6.4.0-150700.53.84.1
kernel-source SLE Module for Development Tools 15 SP7, SLE Module for Basesystem 15 SP7 6.4.0-150700.53.84.1
kernel-default SLE Workstation Extension 15 SP7, SLE Module for Legacy 15 SP7, SLE Module for Basesystem 15 SP7 +2 more 6.4.0-150700.53.84.1
kernel-zfcpdump SLE Module for Basesystem 15 SP7 6.4.0-150700.53.84.1
kernel-obs-build SLE Module for Development Tools 15 SP7 6.4.0-150700.53.84.1
kernel-default-base SLE Module for Basesystem 15 SP7 6.4.0-150700.53.84.1.150700.17.47.1

suse advisories SUSE-SU-2026:4706-1 SUSE-SU-2026:4640-1 SUSE-SU-2026:24316-1 SUSE-SU-2026:24315-1 SUSE-SU-2026:24181-1 SUSE-SU-2026:24182-1

kernel-rt openSUSE Leap 16.0 6.12.0-160000.39.1
dtb-aarch64 openSUSE Leap 16.0 6.12.0-160000.39.1
kernel-64kb openSUSE Leap 16.0 6.12.0-160000.39.1
kernel-syms openSUSE Leap 16.0 6.12.0-160000.39.1
kernel-azure openSUSE Leap 16.0 6.12.0-160000.39.1
kernel-obs-qa openSUSE Leap 16.0 6.12.0-160000.39.1
kernel-source openSUSE Leap 16.0 6.12.0-160000.39.1
kernel-default openSUSE Leap 16.0 6.12.0-160000.39.1

opensuse advisories openSUSE-SU-2026:22091-1

kernel Azure Linux 3.0 6.6.152.1-1

azure linux advisories AZL-96339

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-74465 updated 2026-11-05 cvss 5.5

kernel: net: openvswitch: fix potential UAF on meter attach failure

Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +83 more Red Hat Enterprise Linux 10 kernel
affected: workaround, no fix available “Fix deferred”
Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more
not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: total
Assessed: 23 d ago (2026-10-16)

Exploit prediction

0.15% chance of exploitation in the next 30 days, higher than 4% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	7.8	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected products

Linux Linux

Classification

Technology feeds

Linux kernel rss critical rss

References

Sources

CVE List CVE-2026-74465
NVD CVE-2026-74465

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary