CVE-2026-86128: A NULL pointer dereference vulnerability in Fireware OS's NetFlow packet-processing feature allows a remote, u

Q: How do I fix CVE-2026-86128?

fireware: upgrade to 12.5.21, 12.12.3, 2026.2.3, 2026.3.2. Exact commands for each OS are on this page.

Q: Is CVE-2026-86128 being exploited?

CVE-2026-86128 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-86128 affect?

CVE-2026-86128 affects fireware. Severity is high (CVSS 7.5). A NULL pointer dereference vulnerability in Fireware OS's NetFlow packet-processing feature allows a remote, unauthenticated attacker to cause a denial of service by sending a specially crafted IPv6 packet.

Q: How urgent is CVE-2026-86128?

Priority 39/100. High severity; Remotely exploitable, no login, no user action

Routine

HIGH 7.5REMOTEUPGRADE

CVE-2026-86128 is a high-severity flaw (CVSS 7.5) affecting fireware. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A NULL pointer dereference vulnerability in Fireware OS's NetFlow packet-processing feature allows a remote, unauthenticated attacker to cause a denial of service by sending a specially crafted IPv6 packet.

Why this priority

High severity
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.4% (top 70%)
CISA exploited list	No
Weakness	CWE-476
Published	2026-09-30
Last modified	2026-10-06

Publisher (CNA): WatchGuard Technologies, Inc. · Vendor: watchguard

Last updated 2026-10-06 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-09-30 00:16 UTCPublished CVE record published
2026-10-06 20:42 UTCUpdated Record last modified

watchguard fireware UPGRADE

Affected: >= 12.0 and < 12.5.21 · >= 12.12 and < 12.12.3 · >= 2025.0 and < 2026.2.3 · >= 2026.3 and < 2026.3.2

Fixed in: 12.5.21, 12.12.3, 2026.2.3, 2026.3.2

Safe to downgrade to: a release before 12.0

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-86128?

fireware: upgrade to 12.5.21, 12.12.3, 2026.2.3, 2026.3.2. Exact commands for each OS are on this page.

Is CVE-2026-86128 being exploited?

CVE-2026-86128 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-86128 affect?

CVE-2026-86128 affects fireware. Severity is high (CVSS 7.5). A NULL pointer dereference vulnerability in Fireware OS's NetFlow packet-processing feature allows a remote, unauthenticated attacker to cause a denial of service by sending a specially crafted IPv6 packet.

How urgent is CVE-2026-86128?

Priority 39/100. High severity; Remotely exploitable, no login, no user action

Related CVEs

CVE-2026-3987 HIGH 7.2 UPGRADE A path traversal vulnerability in the Fireware OS Web UI on WatchGuard Firebox systems may allow a privileged
CVE-2026-13368 HIGH 8.1 UPGRADE WatchGuard Fireware OS contains a race condition leading to a use-after-free vulnerability in LDAP authenticat
CVE-2026-13084 HIGH 7.5 UPGRADE A null pointer dereference vulnerability in WatchGuard Fireware OS may allow a remote unauthenticated attacker
CVE-2026-13383 HIGH 7.2 UPGRADE An Out-of-bounds Write vulnerability in WatchGuard Fireware OS ikestubd process could allow an authenticated p
CVE-2026-13384 HIGH 7.2 UPGRADE An Out-of-bounds Write vulnerability in WatchGuard Fireware OS wgagent process could allow an authenticated pr

References

← Back to latest CVEs