Cyber Resilience

CVE-2025-13942

RCE in Zyxel Px3321-T1 Firmware ≤ 5.44\(acjb.1.5\)c0

Published
24 February 2026
Modified
25 February 2026
Patch / advisory
CVSS Score v3.1 9.8
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.011 62th percentile
Risk Priority 73 floored blend · peak EPSS

Summary

CVE-2025-13942 is a critical-severity OS Command Injection (CWE-78) vulnerability in Zyxel Px3321-T1 Firmware. Its CVSS base score is 9.8 (Critical).

Operationally, exploitation aligns with the MITRE ATT&CK technique Command and Scripting Interpreter (T1059); ranked in the top 38% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SI-10 (Information Input Validation) — see the control section below for these in your framework.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

CVE-2025-13942 is a command injection vulnerability (CWE-78) in the UPnP function of Zyxel EX3510-B0 firmware versions through 5.17(ABUP.15.1)C0. Published on 2026-02-24, it carries a CVSS v3.1 base score of 9.8 (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H), reflecting critical severity due to its potential for high-impact confidentiality, integrity, and availability effects.

A remote, unauthenticated attacker can exploit the vulnerability by sending specially crafted UPnP SOAP requests to an affected device, enabling arbitrary operating system command execution. The attack requires no privileges, low complexity, or user interaction, making it highly accessible over the network.

Zyxel has issued a security advisory addressing this command injection vulnerability alongside null pointer dereference issues in certain 4G LTE, 5G NR CPE, DSL Ethernet CPE, fiber ONTs, security routers, and wireless extenders, available at https://www.zyxel.com/global/en/support/security-advisories/zyxel-security-advisory-for-null-pointer-dereference-and-command-injection-vulnerabilities-in-certain-4g-lte-5g-nr-cpe-dsl-ethernet-cpe-fiber-onts-security-routers-and-wireless-extenders-02-24-2026.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

A command injection vulnerability in the UPnP function of the Zyxel EX3510-B0 firmware versions through 5.17(ABUP.15.1)C0 could allow a remote attacker to execute operating system (OS) commands on an affected device by sending specially crafted UPnP SOAP requests.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise Techniques

T1059 Command and Scripting Interpreter Execution
Adversaries may abuse command and script interpreters to execute commands, scripts, or binaries.
T1059.003 Windows Command Shell Execution
Adversaries may abuse the Windows command shell for execution.
T1059.004 Unix Shell Execution
Adversaries may abuse Unix shell commands and scripts for execution.
T1059.001 PowerShell Execution
Adversaries may abuse PowerShell commands and scripts for execution.
T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2025-13943Same product: Zyxel Dx4510-B0
CVE-2025-8693Same product: Zyxel Dx4510-B1
CVE-2026-1460Same product: Zyxel Ee6510-10
CVE-2024-9200Same product: Zyxel Emg6726-B10A
CVE-2026-0711Same product: Zyxel Ee6510-10
CVE-2023-27991Same vendor: Zyxel
CVE-2024-40890Same vendor: Zyxel
CVE-2024-29972Same vendor: Zyxel
CVE-2024-6342Same vendor: Zyxel
CVE-2026-1459Same vendor: Zyxel

Affected Assets

zyxel
wx5610-b0 firmware
≤ 5.18\(acgj.0.5\)c0
zyxel
lte3301-plus firmware
≤ 1.00\(abqu.9\)c0
zyxel
nebula lte3301-plus firmware
≤ 1.18\(acca.6\)v0
zyxel
nr7101 firmware
≤ 1.00\(abuv.12\)b2
zyxel
nebula nr7101 firmware
≤ 1.16\(accc.1\)v0
zyxel
dx4510-b0 firmware
≤ 5.17\(abyl.10.1\)c0
zyxel
dx4510-b1 firmware
≤ 5.17\(abyl.10.1\)c0
zyxel
ee6510-10 firmware
≤ 5.19\(acjq.4.1\)c0
zyxel
emg6726-b10a firmware
≤ 5.13\(abnp.8.2\)c1
zyxel
ex2210-t0 firmware
≤ 5.50\(acdi.2.4\)c0
+8 more product configuration(s) — see NVD for full list

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

Detect
Catch it (NIST detect / respond)

Harden
Shrink the surface (DISA STIG)

Validate
Prove the fix (OWASP ASVS)
  • V1.2.5
  • V1.2.8
  • V15.2.5

Mitigating Controls (NIST 800-53 r5) AI

Developer testing and evaluation can discover missing or incorrect command sanitization during development.

Input validation directly neutralizes or rejects special characters that would otherwise alter OS command structure.

Least privilege reduces the permissions available to any process that could be subverted by injected commands.

Least functionality restricts available OS commands and interpreters, limiting the blast radius of injection.

Secure engineering principles require proper neutralization of untrusted input before command construction.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

PR.PS-06's SDLC practices directly require secure coding and input handling that blocks command-injection defects, yet the single broad outcome leaves many specific neutralization vectors and verification gaps unaddressed.

PR.PS-02 partial match
prevents

Routine patching/maintenance can remediate known command-injection CVEs in dependencies (partial forward) but does nothing to stop developers from introducing improper neutralization in custom code (none reverse).

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

finds

Security testing and code review target insecure use of operating-system command interfaces, catching command-injection flaws introduced during development.

References