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Digital Watchdog VMAX EUVDEUVD-2026-79952

| CVE-2026-66887 CRITICAL
Missing Authorization (CWE-862)
2026-09-15 ics-cert@hq.dhs.gov GHSA-294r-hwg8-m55w
9.4
CVSS 4.0 · Vendor: hq
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Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

  1. Access
    Gain adjacent-network access to recorder
  2. Delivery
    Identify unprotected state-changing CGI
  3. Exploit
    Send request bypassing session check
  4. Execution
    Alter config or recordings
  5. Impact
    Compromise surveillance integrity/availability

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A01:2025 - Broken Access Control
ASVS 5.0
V8 - Authorization Authorization checks on every request
MITRE ATT&CK

1 technique across 1 tactic: Privilege Escalation

The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up.

Exploitation Conditions

Requires network-adjacent access (AV:A) to a Digital Watchdog VMAX A1/A1 G4/IP G4 NVR or VG4/VA1G4 recorder - i.e., the attacker must reach the device's web/CGI interface on the local segment. No authentication (PR:N) and no user interaction (UI:N) are needed: state-changing CGI endpoints process requests without performing session or authorization checks, so any reachable request is honored. The primary limiting factor is the adjacent-network attack vector - the flaw is not scored as internet-remote - but this protection collapses if the recorder is exposed via port-forwarding or placed on a flat/reachable network, a common real-world deployment pattern for surveillance appliances. No non-default configuration is required to trigger the flaw itself.

Impact

This is a genuine high-priority issue in the context of the affected devices, but with an important limiter. The CVSS 4.0 base score of 9.4 is driven by unauthenticated (PR:N), low-complexity (AC:L) access with no user interaction, producing full compromise of the vulnerable device (VC:H/VI:H/VA:H) AND high subsequent-system impact (SC:H/SI:H/SA:H) - consistent with CWE-862 Missing Authorization, where state-changing CGI endpoints execute without session/authorization checks. The key mitigating signal is AV:A (adjacent network) rather than AV:N: the vendor/ICS-CERT assessment scopes exploitation to an attacker already on the same network segment, not the open internet, which meaningfully reduces mass-exploitation likelihood for properly segmented deployments. No EPSS score, no POC, and no CISA KEV entry are present in the provided data, so there is no evidence of active exploitation - the risk is assessed on the vulnerability's intrinsic severity and the trivial exploitation mechanics, not on observed attacks. The signals are internally consistent (no conflict between CVSS and description); the main caveat is that DVR/NVR appliances are frequently exposed to larger networks or the internet via port-forwarding in practice, which would effectively elevate the real-world attack vector beyond the adjacent-network assumption. Verify network exposure of specific installations before de-prioritizing.

Exploit ScenarioDerived

An attacker with access to the local network segment hosting a Digital Watchdog VMAX/VG4/VA1G4 recorder sends direct HTTP requests to state-changing CGI endpoints, which execute without any session validation or authorization check. This lets the attacker alter device configuration, manipulate recordings, or disrupt the surveillance system without credentials. No public exploit code is identified at time of analysis, though the missing-authorization mechanics are trivial to reproduce.

Emergency Immediate action required. Why: CRITICAL + active threat signals, no patch available.
No patch listed yet 0.2% exploitation probability (EPSS)

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AnalysisAIv1 – Sep 16, 2026

Missing authorization and absent session validation on state-changing CGI endpoints in Digital Watchdog VMAX A1 PLUS, VMAX A1 G4 DVR, VMAX IP G4 NVR, VG4 Recorder and VA1G4 Recorder devices let an unauthenticated attacker on the adjacent network invoke privileged device operations - including configuration, account and recording-management functions - simply by sending requests to a reachable endpoint, with no credentials or user interaction required. The independent assessment scores this CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H, i.e. high confidentiality, integrity and availability impact across a scope change, because the compromised CGI layer can affect the broader device and its downstream consumers. The main limiter is the adjacent-network attack vector rather than internet-remote reachability, but that protection disappears whenever a recorder is port-forwarded or sits on a flat network; no public exploit code was identified at time of analysis and the issue is not listed in CISA KEV.

RemediationAI

No vendor-released patch or exact fixed version could be confirmed from the supplied data; firmware for these appliances is distributed through Digital Watchdog's downloads page (https://digital-watchdog.com/downloads/), so the first step is to check that page and the CISA advisory ICSA-26-258-01 for a firmware update covering VMAX A1 PLUS, VMAX A1 G4 DVR, VMAX IP G4 NVR, VG4 Recorder and VA1G4 Recorder, and apply it as soon as it is published. Until a fix is available, the highest-value compensating control is to remove the attack path entirely: keep the recorders off any routable or internet-facing path, eliminate port-forwarding to their web/CGI ports, and place them on a dedicated, firewalled VLAN that only the management workstation or VMS can reach - the trade-off is that remote viewing and third-party integrations must be re-architected through a VPN or reverse-proxy with authentication rather than direct access. Where the deployment still requires remote access, front the device with an authenticating reverse proxy or VPN and block direct HTTP/HTTPS to the CGI interface at the perimeter; note that a proxy cannot fix the missing checks inside the firmware and only reduces exposure. Also segment recording storage and any downstream VMS integrations from general user networks, since the scope-changed impact means a compromised recorder can affect systems that trust it. Monitor for anomalous unauthenticated POST/GET requests to CGI paths from unexpected hosts as a detection measure while remediation is pending.

Affected VersionsENISA

VA1G4 Recorder All
VMAX A1 PLUS All
VMAX A1 G4 DVR All
VG4 Recorder All
VMAX IP G4 NVR All

Affects your stack

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Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

The root cause is CWE-862 (Missing Authorization): the affected Digital Watchdog appliances - embedded Linux-based network video recorders (NVR) and digital video recorders (DVR) in the VMAX A1/A1 G4/IP G4 and VG4/VA1G4 families - expose a web management interface backed by CGI programs, and the state-changing CGI handlers neither verify that the caller holds an authenticated session nor perform any authorization check on the requested action. The description explicitly notes that state-changing CGIs lack authorization and that session checks are not performed, meaning the request handler executes the action as long as it is syntactically valid. This is a classic broken-access-control pattern in embedded appliance firmware, where the web UI is treated as implicitly trusted. With scope changed (S:C) in the assessed vector, a successful request can affect resources beyond the immediately vulnerable component, such as stored video, configured integrations, or downstream systems that consume the device. CISA's ICS advisory ICSA-26-258-01 assigns it the tag Authentication Bypass, and EUVD lists every version of the five product families as affected, indicating the defect is architectural in the firmware line rather than introduced by a single release.

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

Vendor (hq) PRIMARY 9.4 CRITICAL
CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
vuln.today AI 9.6 CRITICAL

Adjacent-network access to unauthenticated state-changing CGIs (AV:A, PR:N, AC:L); missing authorization yields full device compromise with impact beyond the vulnerable component, so S:C and C/I/A:H.

3.1 AV:A/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
4.0 AV:A/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H

Primary rating from Vendor (hq).

CVSS VectorVendor: hq

Attack Vector
Adjacent
Attack Complexity
Low
Attack Requirements
None
Privileges Required
None
User Interaction
None
Vulnerable system: Confidentiality
High
Vulnerable system: Integrity
High
Vulnerable system: Availability
High
Subsequent system: Confidentiality
High
Subsequent system: Integrity
High
Subsequent system: Availability
High

DescriptionCVE.org

The affected products are missing authorization on state-changing CGIs and session checks are not performed.

Executive ViewAI

Why It Matters

An unauthenticated authorization flaw in Digital Watchdog's VMAX A1 PLUS, VMAX A1 G4, VMAX IP G4, VG4 and VA1G4 recorders and DVR/NVRs (CVE-2026-66887, CVSS 9.4) allows anyone with access to the same network segment to seize control of configuration, account and recording-management functions without credentials. Because these devices typically share flat networks with cameras, operator workstations and building systems, a single compromised or guest-connected host could silently alter, disable or expose video evidence across an entire site. With no vendor patch available at time of analysis, leadership should treat exposed and port-forwarded recorders as a standing physical-security and evidentiary risk until they are isolated, and should weigh the regulatory and legal exposure of unavailable or tampered video retention.

Business Impact: High
Compensating Controls

No vendor-released patch identified at time of analysis; interim mitigations: remove all internet exposure and port forwarding, place recorders on an isolated dedicated VLAN with deny-by-default ACLs against user and guest networks, restrict CGI/web management access to hardened administrative hosts only, rotate device and integration credentials, disable unnecessary remote services, enable and monitor configuration-change logging, and physically restrict or monitor the network ports these devices attach to.

Threat Intelligence Overview

EPSS Score
0.2%
Top 90% exploitable
Prevalence
Medium
Digital Watchdog DVR/NVR video-surveillance appliances, common in commercial security installs
Threat Intel
1
1 source
Data Quality
6 sources
Confidence: High

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity CRITICAL
CISA KEV No
Public POC No
EPSS 0.2%
Patch available No
Active threat Yes
Deciding rule
CRITICAL + active threat signals, no patch available
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived
Scheduled
Exploitation· derived
None
System Exposure· derived
Controlled
Automatable· derived
No
Human Impact
High

Priority Score

57
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +47
PoC: 0
Weaponized: 0
Threat intel: +10
Gov advisory: 0

Attack Technique

Authentication bypass attacks exploit flaws in the verification mechanisms that control access to systems and applications.

Threat IntelligenceMISP

CISA Advisories
Sources: CISA (public domain)

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