CyberSecBulletin
CVE-2026-19316NVD status: Deferred

Fireware OS: Double Free

Published Updated By the CyberSecBulletin desk

CVE-2026-19316 is a high-severity double free vulnerability in Fireware OS from WatchGuard, with a CVSS 4.0 base score of 8.7 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists versions 2026.2.2, 12.12.2, 2026.3.1 as the first without the flaw, so updating Fireware OS to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.54% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update Fireware OS to 2026.2.2 or 12.12.2 or 2026.3.1 or 12.5.20, whichever matches your release line, or a later version.
  2. Read the advisory on psirt.watchguard.com for workarounds and exact fixed builds.
  3. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.

Affected products and versions

VendorProductAffected versionsFixed in
WatchGuardFireware OS2025.0 up to, but not including, 2026.2.2; 12.0 up to, but not including, 12.12.2; 2026.3 up to, but not including, 2026.3.1; 12.0 up to, but not including, 12.5.202026.2.2, 12.12.2, 2026.3.1, 12.5.20

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Attack requirements
NoneThe attack does not depend on a particular deployment or configuration.
Privileges required
NoneNo account or login is needed.
User interaction
NoneNo action by a victim is required.
Confidentiality (vulnerable system)
NoneNo loss of confidentiality on the vulnerable system.
Integrity (vulnerable system)
NoneNo loss of integrity on the vulnerable system.
Availability (vulnerable system)
HighSerious loss of availability on the vulnerable system.
Confidentiality (other systems)
NoneNo loss of confidentiality on systems beyond the vulnerable one.
Integrity (other systems)
NoneNo loss of integrity on systems beyond the vulnerable one.
Availability (other systems)
NoneNo loss of availability on systems beyond the vulnerable one.

Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X. Scored by CNA.

Official description

A double-free vulnerability in the WatchGuard Fireware OS iked process allows a remote unauthenticated attacker to create a Denial of Service (DoS) condition in VPN processing by sending specially crafted network traffic.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Double Free

The product calls free() twice on the same memory address.

How developers prevent this class of flaw

  • Choose a language that provides automatic memory management.
  • Ensure that each allocation is freed only once. After freeing a chunk, set the pointer to NULL to ensure the pointer cannot be freed again. In complicated error conditions, be sure that clean-up routines respect the state of allocation properly. If the language is object oriented, ensure that object destructors delete each chunk of memory only once.
  • Use a static analysis tool to find double free instances.

More Double Free vulnerabilities (CWE-415)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
  3. Record last changed materially (score, affected products, status or references).

References

Other vulnerabilities in Fireware OS

All Fireware OS vulnerabilities

Recent Double Free vulnerabilities

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