CVE-2025-8693

HighRCE

Published: 18 November 2025

Published

18 November 2025

Modified

15 December 2025

KEV Added

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Patch

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CVSS Score 8.8 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS Score 0.0013 32.1th percentile

Risk Priority 18 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2025-8693 is a high-severity OS Command Injection (CWE-78) vulnerability in Zyxel Ex3300-T0 Firmware. Its CVSS base score is 8.8 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Network Device CLI (T1059.008); ranked at the 32.1th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified are NIST 800-53 SI-10 (Information Input Validation) and SI-2 (Flaw Remediation).

Threat & Defense at a Glance

What attackers do: exploitation maps to Network Device CLI (T1059.008) and 1 other technique. What defenders deploy: see the NIST 800-53 controls recommended below.

Threat & Defense Details

Mitigating Controls (NIST 800-53 r5)AI

SI-10 Information Input Validation good match

prevent

Directly validates inputs like the 'priv' parameter to block command injection payloads from executing OS commands.

SI-2 Flaw Remediation good match

prevent

Mandates timely patching of the specific firmware flaw enabling post-authentication command injection.

AC-6 Least Privilege partial match

prevent

Enforces least privilege for authenticated low-privilege users to limit the scope and impact of injected OS commands.

MITRE ATT&CK Enterprise TechniquesAI

T1059.008 Network Device CLI Execution

Adversaries may abuse scripting or built-in command line interpreters (CLI) on network devices to execute malicious command and payloads.

attack.mitre.org →

T1210 Exploitation of Remote Services Lateral Movement

Adversaries may exploit remote services to gain unauthorized access to internal systems once inside of a network.

attack.mitre.org →

Why these techniques?

Post-authentication command injection in network device firmware directly enables arbitrary OS command execution (T1059.008: Network Device CLI) through exploitation of a remote management service (T1210: Exploitation of Remote Services).

Confidence: HIGH · MITRE ATT&CK Enterprise v19.0

NVD Description

A post-authentication command injection vulnerability in the "priv" parameter of Zyxel DX3300-T0 firmware version 5.50(ABVY.6.3)C0 and earlier could allow an authenticated attacker to execute operating system (OS) commands on an affected device.

Deeper analysisAI

CVE-2025-8693 is a post-authentication command injection vulnerability (CWE-78) in the "priv" parameter of Zyxel DX3300-T0 firmware version 5.50(ABVY.6.3)C0 and earlier. This flaw allows an authenticated attacker to execute arbitrary operating system commands on the affected device. The vulnerability carries a CVSS v3.1 base score of 8.8 (AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H) and was published on 2025-11-18T02:15:45.410.

An attacker with low-privilege authenticated access (PR:L) can exploit this vulnerability remotely over the network (AV:N) with low attack complexity (AC:L) and without requiring user interaction (UI:N). Successful exploitation enables execution of OS commands, resulting in high impacts to confidentiality, integrity, and availability (C:H/I:H/A:H), potentially leading to full device compromise.

The Zyxel security advisory provides details on mitigation, available at https://www.zyxel.com/global/en/support/security-advisories/zyxel-security-advisory-for-uncontrolled-resource-consumption-and-command-injection-vulnerabilities-in-certain-4g-lte-5g-nr-cpe-dsl-ethernet-cpe-fiber-onts-security-routers-and-wireless-extenders-11-18-2025.