Fireware OS: Improper Link Resolution Before File Access
CVE-2026-90464 is a high-severity improper link resolution before file access vulnerability in Fireware OS from WatchGuard, with a CVSS 4.0 base score of 7.2 out of 10. It can be exploited remotely over the network by an attacker with a low-privileged account, without any action from a user. The record lists versions 2026.4, 12.12.4, 12.5.22 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 0.36% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Fireware OS to 2026.4 or 12.12.4 or 12.5.22, whichever matches your release line, or a later version.
- Read the advisory on psirt.watchguard.com for workarounds and exact fixed builds.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| WatchGuard | Fireware OS | 2025.1 up to, but not including, 2026.4; 12.0 up to, but not including, 12.12.4; 12.0 up to, but not including, 12.5.22 | 2026.4, 12.12.4, 12.5.22 |
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
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Confidentiality (vulnerable system)
- NoneNo loss of confidentiality on the vulnerable system.
- Integrity (vulnerable system)
- HighSerious 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:L/UI:N/VC:N/VI:H/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
An external control of file path vulnerability in a WatchGuard Fireware OS firewall diagnostic command allows a remote, authenticated attacker with at least read-only (Device Monitor) privileges and access to the management CLI to create, truncate, or overwrite arbitrary files and modify kernel parameters with root privileges by submitting a specially crafted command. Written content is limited to numeric values.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Link Resolution Before File Access
The product attempts to access a file based on the filename, but it does not properly prevent that filename from identifying a link or shortcut that resolves to an unintended resource.
How developers prevent this class of flaw
- Follow the principle of least privilege when assigning access rights to entities in a software system. Denying access to a file can prevent an attacker from replacing that file with a link to a sensitive file. Ensure good compartmentalization in the system to provide protected areas that can be trusted.
More Improper Link Resolution Before File Access vulnerabilities (CWE-59)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Advisories
Other vulnerabilities in Fireware OS
- 9.2 Critical severity
- 9.2 Critical severity
- 7.1 High severity
- 7.2 High severity
- 9.2 Critical severity
- 8.7 High severity
Recent Improper Link Resolution Before File Access vulnerabilities
- 7.5 High severity
- 10.0 Critical severity
- 9.9 Critical severity
- 7.2 High severity
- 7.0 High severity
- 7.8 High severity
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