● Not verified

How to Fix CVE-2026-23046: Critical Vulnerability in Linux

Q: Is CVE-2026-23046 being exploited in the wild?

Public exploitation has not been confirmed by CISA at the time of writing. Treat the patch as time-sensitive anyway; reports often lag actual abuse.

Q: Will a WAF or IDS rule fully mitigate CVE-2026-23046?

No. Network-layer filters can reduce noise and slow opportunistic scanners, but they will not stop a determined attacker. The vendor patch is the only durable fix.

Q: How long should I plan for the upgrade?

Typical vendor-documented upgrade windows for Linux run from a few minutes to under an hour depending on cluster size. Test in a staging environment first and follow the vendor's documented HA upgrade order.

Other vulnerabilities in the same area that are worth patching alongside this one:

How to Fix CVE-2026-43358: Security Vulnerability in Linux — Security Vulnerability in Linux
How to Fix CVE-2026-23372: Critical Vulnerability in Linux — Critical Vulnerability in Linux
How to Fix CVE-2026-31415: Security vulnerability in Linux , Security vulnerability in Linux
How to Fix CVE-2026-23404: Linux (Bundle Sibling) , Linux (Bundle Sibling)
How to Fix CVE-2026-31766: drm/amdgpu: validate doorbell_offset in Linux , drm/amdgpu: validate doorbell_offset in Linux

*By Sai Kiran Pandrala*

⚡ At a glance


Severity	Not verified - see advisory
Actively exploited?	Not currently listed in CISA KEV
Affected	4944be2f5ad8c74b93e4e272f3a0f1a136bbc438 < a5e2d902f64c76169c771f584559c82b588090e3, 4944be2f5ad8c74b93e4e272f3a0f1a136bbc438 < acb4bc6e1ba34ae1a34a9334a1ce8474c909466e, 6.15
Fixed in	0, 6.18.6, 6.19
Type (CWE)	Not verified

What is CVE-2026-23046?

CVE-2026-23046 is a security flaw in Linux. In the Linux kernel, the following vulnerability has been resolved: virtio_net: fix device mismatch in devm_kzalloc/devm_kfree Initial rss_hdr allocation uses virtio_device->device, but virtnet_set_queues() frees using net_device->device. This device mismatch causing below devres warning [ 3788.514041] ------------[ cut here ]------------ [ 3788.514044] WARNING: drivers/base/devres.c:1095 at devm_kfree+0x84/0x98, CPU#16: vdpa/1463 [ 3788.514054] Modules linked in: octep_vdpa virtio_net virtio_vdpa [last unloaded: virtio_vdpa] [ 3788.514064] CPU: 16 UID: 0 PID: 1463 Comm: vdpa Tainted: G W 6.18.0 #10 PREEMPT [ 3788.514067] Tainted: [W]=WARN [ 3788.514069] Hardware name: Marvell CN106XX board (DT) [ 3788.514071] pstate: 63400009 (nZCv daif +PAN -UAO +TCO +DIT -SSBS BTYPE=--) [ 3788.514074] pc : devm_kfree+0x84/0x98 [ 3788.514076] lr : devm_kfree+0x54/0x98 [ 3788.514079] sp : ffff800084e2f220 [ 3788.514080] x29: ffff800084e2f220 x28: ffff0003b2366000 x27: 000000000000003f [ 3788.514085] x26: 000000000000003f x25: ffff000106f17c10 x24: 0000000000000080 [ 3788.514089] x23: ffff00045bb8ab08 x22: ffff00045bb8a000 x21: 0000000000000018 [ 3788.514093] x20: ffff0004355c3080 x19: ffff00045bb8aa00 x18: 0000000000080000 [ 3788.514098] x17: 0000000000000040 x16: 000000000000001f x15: 000000000007ffff [ 3788.514102] x14: 0000000000000488 x13: 0000000000000005 x12: 00000000000fffff [ 3788.514106] x11: ffffffffffffffff x10: 0000000000000005 x9 : ffff800080c8c05c [ 3788.514110] x8 : ffff800084e2eeb8 x7 : 0000000000000000 x6 : 000000000000003f [ 3788.514115] x5 : ffff8000831bafe0 x4 : ffff800080c8b010 x3 : ffff0004355c3080 [ 3788.514119] x2 : ffff0004355c3080 x1 : 0000000000000000 x0 : 0000000000000000 [ 3788.514123] Call trace: [ 3788.514125] devm_kfree+0x84/0x98 (P) [ 3788.514129] virtnet_set_queues+0x134/0x2e8 [virtio_net] [ 3788.514135] virtnet_probe+0x9c0/0xe00 [virtio_net] [ 3788.514139] virtio_dev_probe+0x1e0/0x338 [ 3788.514144] really_probe+0xc8/0x3a0 [ 3788.514149] __driver_probe_device+0x84/0x170 [ 3788.514152] driver_probe_device+0x44/0x120 [ 3788.514155] __device_attach_driver+0xc4/0x168 [ 3788.514158] bus_for_each_drv+0x8c/0xf0 [ 3788.514161] __device_attach+0xa4/0x1c0 [ 3788.514164] device_initial_probe+0x1c/0x30 [ 3788.514168] bus_probe_device+0xb4/0xc0 [ 3788.514170] device_add+0x614/0x828 [ 3788.514173] register_virtio_device+0x214/0x258 [ 3788.514175] virtio_vdpa_probe+0xa0/0x110 [virtio_vdpa] [ 3788.514179] vdpa_dev_probe+0xa8/0xd8 [ 3788.514183] really_probe+0xc8/0x3a0 [ 3788.514186] __driver_probe_device+0x84/0x170 [ 3788.514189] driver_probe_device+0x44/0x120 [ 3788.514192] __device_attach_driver+0xc4/0x168 [ 3788.514195] bus_for_each_drv+0x8c/0xf0 [ 3788.514197] __device_attach+0xa4/0x1c0 [ 3788.514200] device_initial_probe+0x1c/0x30 [ 3788.514203] bus_probe_device+0xb4/0xc0 [ 3788.514206] device_add+0x614/0x828 [ 3788.514209] _vdpa_register_device+0x58/0x88 [ 3788.514211] octep_vdpa_dev_add+0x104/0x228 [octep_vdpa] [ 3788.514215] vdpa_nl_cmd_dev_add_set_doit+0x2d0/0x3c0 [ 3788.514218] genl_family_rcv_msg_doit+0xe4/0x158 [ 3788.514222] genl_rcv_msg+0x218/0x298 [ 3788.514225] netlink_rcv_skb+0x64/0x138 [ 3788.514229] genl_rcv+0x40/0x60 [ 3788.514233] netlink_unicast+0x32c/0x3b0 [ 3788.514237] netlink_sendmsg+0x170/0x3b8 [ 3788.514241] __sys_sendto+0x12c/0x1c0 [ 3788.514246] __arm64_sys_sendto+0x30/0x48 [ 3788.514249] invoke_syscall.constprop.0+0x58/0xf8 [ 3788.514255] do_el0_svc+0x48/0xd0 [ 3788.514259] el0_svc+0x48/0x210 [ 3788.514264] el0t_64_sync_handler+0xa0/0xe8 [ 3788.514268] el0t_64_sync+0x198/0x1a0 [ 3788.514271] ---[ end trace 0000000000000000 ]--- Fix by using virtio_device->device consistently for allocation and deallocation

Why this CVE matters

Unpatched network-facing software is the leading initial-access vector in public breach reporting. Treat any CVSS-9 class flaw on an internet-reachable system as urgent, regardless of whether public exploit code has been observed yet.

For deployments of Linux that have been exposed to the public internet during the disclosure window, the operating assumption should be that scanning has already happened. Even where exploitation has not been publicly observed, scanning for the vulnerable fingerprint is cheap and routine. Patching closes the door; log review and credential rotation close out the rest of the response.

Am I affected?

You are affected if your installation matches any of these version ranges:

Linux: 4944be2f5ad8c74b93e4e272f3a0f1a136bbc438 < a5e2d902f64c76169c771f584559c82b588090e3
Linux: 4944be2f5ad8c74b93e4e272f3a0f1a136bbc438 < acb4bc6e1ba34ae1a34a9334a1ce8474c909466e
Linux: 6.15

Check your installed version against the list above. If you cannot determine the version, treat the system as affected and follow the upgrade path below.

Run uname -r to read the kernel release. Compare against the affected ranges; on distro kernels, also check the package version with dpkg -l linux-image-$(uname -r) or rpm -q kernel.

How to fix CVE-2026-23046

Read the vendor advisory in full: https://git.kernel.org/stable/c/a5e2d902f64c76169c771f584559c82b588090e3
Upgrade Linux to 0, 6.18.6, 6.19 or a later version listed in the vendor advisory.
Back up the configuration (and database, where applicable) before upgrading.
Apply the patch in a maintenance window. For HA pairs, upgrade the standby node first, fail over, then upgrade the former primary.
Restart the affected service so the patched binary loads, then verify the new version (see verification section).

Ubuntu / Debian

_Verify the exact patched build against the vendor advisory: https://git.kernel.org/stable/c/a5e2d902f64c76169c771f584559c82b588090e3_


sudo apt-get update
sudo apt-get install --only-upgrade linux-image-generic
dpkg -s linux-image-generic | grep -i version

RHEL / Rocky / AlmaLinux / Fedora


sudo dnf upgrade --refresh linux-image-generic -y
rpm -q linux-image-generic

openSUSE


sudo zypper refresh
sudo zypper update linux-image-generic
rpm -q linux-image-generic

Bash detect / upgrade / verify runner (Linux)

_Verify the exact patched build against the vendor advisory: https://git.kernel.org/stable/c/a5e2d902f64c76169c771f584559c82b588090e3_


#!/usr/bin/env bash
# CVE-2026-23046 remediation runner. Re-runnable; exits non-zero on failure.
set -euo pipefail
log() { printf '%s %s\n' "$(date -Is)" "$*" | tee -a /var/log/cve-2026-23046-fix.log; }

PKG="linux-image-generic"
TARGET_VERSION="6.18.6 or 6.19"

log "Detect: reading current $PKG version"
if command -v dpkg >/dev/null 2>&1; then
    current=$(dpkg-query -W -f='${Version}' "$PKG" 2>/dev/null || echo "not-installed")
elif command -v rpm >/dev/null 2>&1; then
    current=$(rpm -q --qf '%{VERSION}-%{RELEASE}' "$PKG" 2>/dev/null || echo "not-installed")
else
    current="unknown"
fi
log "Current: $current (target per advisory: $TARGET_VERSION)"

log "Backup: snapshotting /etc/$PKG if present"
backup="/var/backups/cve-2026-23046-$(date +%Y%m%d-%H%M)"
mkdir -p "$backup"
[ -d "/etc/$PKG" ] && cp -a "/etc/$PKG" "$backup/" || true

log "Upgrade: applying vendor patch"
if command -v apt-get >/dev/null 2>&1; then
    sudo apt-get update -qq
    sudo apt-get install -y --only-upgrade "$PKG"
elif command -v dnf >/dev/null 2>&1; then
    sudo dnf upgrade -y "$PKG"
elif command -v yum >/dev/null 2>&1; then
    sudo yum update -y "$PKG"
fi

log "Verify: re-reading $PKG version"
if command -v dpkg >/dev/null 2>&1; then
    after=$(dpkg-query -W -f='${Version}' "$PKG")
else
    after=$(rpm -q --qf '%{VERSION}-%{RELEASE}' "$PKG")
fi
log "After: $after"

if [ "$after" != "$current" ]; then
    log "SUCCESS: $PKG upgraded"
else
    log "WARN: version unchanged. Confirm the patched build is in your repository."
    exit 1
fi

Verify the fix landed


# 1. Confirm the running version matches the patched build
#    (target per advisory: 6.18.6 or 6.19)
#    Use the platform-specific version probe shown above.

# 2. Re-scan the host with your vulnerability scanner (Nessus, Qualys, Tenable,
#    Rapid7, OpenVAS). The scanner should no longer flag CVE-2026-23046.

# 3. Inspect service and kernel logs for crash-loops or rollback events
journalctl --since "10 minutes ago" | grep -iE 'error|fail|panic'
dmesg --since "10 minutes ago" | tail -50

If you cannot patch immediately

No official workaround exists beyond restricting network exposure to the affected component. Apply the vendor patch as the primary remediation.

How to verify the fix worked

After applying the patch, verify the running version in the product's admin UI or via the vendor-documented CLI command.
Confirm the patched build matches the version listed in the vendor advisory.
Run an authenticated vulnerability scan with a current signature set and confirm the scanner no longer flags CVE-2026-23046.
Review logs for the entire pre-patch window for indicators of compromise listed in the vendor or CISA advisory.
Confirm any network-layer mitigations that were applied as a stopgap have been reverted (or left in place intentionally) once the patch is verified.

If your installation was internet-reachable during the disclosure window, treat log review as part of the remediation rather than an optional follow-up. Look for log entries that do not match your normal request patterns, especially repeated requests to the same uncommon endpoint, and any administrative changes you cannot tie back to a known operator.

Frequently asked questions

Is CVE-2026-23046 being exploited in the wild?