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Vulnerabilities/CVE-2026-3987Public Intelligence Dossier
Source: watchguard · Limited verification•Last verified: •Collection Degraded
CVE-2026-3987Unknown / EvaluatingHIGH (raw)CVSS 8.6CWE-22

A path traversal vulnerability in the Fireware OS Web UI on WatchGuard Firebox systems may allow a privileged authenticated remote attacker to execute arbitrary code in the context of an elevated system process.

Published: 02 Apr 2026•Last updated: 27 Oct 2026, 02:40 AM IST•Source identifier: 5d1c2695-1a31-4499-88ae-e847036fd7e3
Dossier completeness: source-provided sections 2 / 3 · rule guidance available. Missing source facts count as incomplete.
Official source
CISA KEV catalog
Unknown
KEV status was not determined.
CVSS score
8.6HIGH (raw)
CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/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
Metric source5d1c2695-1a31-4499-88ae-e847036fd7e3
EPSS probability
0.7%0.007
Percentile53rd
Weakness type
CWE-22
No further CWE recorded
Remediation
Patch status unknown
No fixed version or KB recorded

Why It Matters

Analysis dossier

Why It Matters

A path traversal vulnerability in the Fireware OS Web UI on WatchGuard Firebox systems may allow a privileged authenticated remote attacker to execute arbitrary code in the context of an elevated system process.

SOC priority

High

Actively exploited (source statement)

Unknown

Publicly disclosed

Unknown

Risk basis: SOC ecosystem technology relevance; HIGH severity; Source severity; no confirmed exploitation signal

Affected Products & Remediation

1 source-backed product
Affected products and versions (source)
  • watchguard fireware · >= 2025.1 < 2026.2; >= 12.6.1 < 12.12 · NVD CPE · Source
NVD applicability prerequisites: cpe:2.3:h:watchguard:firebox_m295:-:*:*:*:*:*:*:*, cpe:2.3:h:watchguard:firebox_m395:-:*:*:*:*:*:*:*, cpe:2.3:h:watchguard:firebox_m495:-:*:*:*:*:*:*:*, cpe:2.3:h:watchguard:firebox_m595:-:*:*:*:*:*:*:*, cpe:2.3:h:watchguard:firebox_m695:-:*:*:*:*:*:*:*, cpe:2.3:h:watchguard:firebox_t115-w:-:*:*:*:*:*:*:*, cpe:2.3:h:watchguard:firebox_t125:-:*:*:*:*:*:*:*, cpe:2.3:h:watchguard:firebox_t125-w:-:*:*:*:*:*:*:*, cpe:2.3:h:watchguard:firebox_t145:-:*:*:*:*:*:*:*, cpe:2.3:h:watchguard:firebox_t145-w:-:*:*:*:*:*:*:*. These are conditions, not proof that an environment is exposed or unaffected.
Recorded patch / KBNot provided by source

Vendor or catalog guidance (source)

Not provided by source

Known exploitation (source facts)

Only what a source states. Unknown means no source has said either way; it is not "not exploited".

CISA KEV
Unknown
Exploited (source statement)
Unknown
Publicly disclosed (source)
Unknown

Suggested hunting (rule-based inference)

SecOps Signal recommendation (rule-based inference). These steps are hunting hypotheses from the vulnerability class; they do not state or imply that exploitation occurred here or anywhere.

Matched path-traversal (CWE-22)

Exposure

  1. Locate affected deployments and the path-handling endpoint named by the advisory.Telemetry: Application access logs · The affected path must come from the source, not the CWE alone. · Rule path-traversal

Exploitation evidence

  1. Review requests to that endpoint for traversal encodings and unusual file responses.Telemetry: Application access logs · Such patterns are a hypothesis to validate against normal traffic. · Rule path-traversal

Response

  1. Verify the source-stated fix and retest the affected path.Telemetry: Application change records · The exact remediation depends on the source advisory. · Rule path-traversal

CISA KEV Record

CISA KEV status was not determined for this record.

Change History & Source Data

— No recorded material change

CNA / source
5d1c2695-1a31-4499-88ae-e847036fd7e3
Record status · verification
UPDATED · NVD API
CPE
cpe:2.3:o:watchguard:fireware:*:*:*:*:*:*:*:*, cpe:2.3:h:watchguard:firebox_m295:-:*:*:*:*:*:*:*, cpe:2.3:h:watchguard:firebox_m395:-:*:*:*:*:*:*:*, cpe:2.3:h:watchguard:firebox_m495:-:*:*:*:*:*:*:*, cpe:2.3:h:watchguard:firebox_m595:-:*:*:*:*:*:*:*, cpe:2.3:h:watchguard:firebox_m695:-:*:*:*:*:*:*:*, cpe:2.3:h:watchguard:firebox_t115-w:-:*:*:*:*:*:*:*, cpe:2.3:h:watchguard:firebox_t125:-:*:*:*:*:*:*:*, cpe:2.3:h:watchguard:firebox_t125-w:-:*:*:*:*:*:*:*, cpe:2.3:h:watchguard:firebox_t145:-:*:*:*:*:*:*:*

Evidence & Provenance

3 public sources
watchguard.comSource recordnvd.nist.govSource recordpsirt.watchguard.comSource record

Linked by the query's stored exact CVE association. Review required tables and validation status before use.

Detection Hunting Query
Target: DeviceTvmSoftwareVulnerabilities•Defender XDR
Detect endpoints exposed to CVE-2026-3987
Purpose: Exposure assessment (Category: Exposure Check)Why linked: Query metadata names CVE-2026-3987
DeviceTvmSoftwareVulnerabilities| where CveId == "CVE-2026-3987"| project DeviceId, DeviceName, OSPlatform, OSVersion, SoftwareVendor, SoftwareName, SoftwareVersion, CveId, VulnerabilitySeverityLevel, RecommendedSecurityUpdate, RecommendedSecurityUpdateId| sort by VulnerabilitySeverityLevel desc
Schema Checked · Not runtime validatedSource: SecOps Signal deterministic template · Limited verificationStatic screening: Passed structure and schema checks; tenant execution is not verified.
Open KQL Library

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Correlated briefings

SecOps Signal surfaces public advisory facts only. A missing value means the source has not published it, not that your environment is unaffected. No tenant inventory is connected.