Cyber Resilience

CVE-2025-4999

Command Injection in Linksys Fgw3000-Ah Firmware ≤ 1.0.17.000000

Command Injection
Published
20 May 2025
Modified
17 June 2026
Patch / advisory
View advisory
CVSS Score v4 5.3
Click a component to see what it means
Raw vectorCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/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
EPSS Score 0.078 94th percentile
Risk Priority 45 floored blend · peak EPSS

CVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.

Summary

CVE-2025-4999 is a medium-severity Injection (CWE-74) vulnerability in Linksys Fgw3000-Ah Firmware. Its CVSS base score is 5.3 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Command and Scripting Interpreter (T1059); ranked in the top 6% 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.

A command injection vulnerability affects the Linksys FGW3000-AH and FGW3000-HK routers up to firmware version 1.0.17.000000. It resides in the sub_4153FC function within the /cgi-bin/sysconf.cgi HTTP POST Request Handler and is triggered by manipulation of the supplicant_rnd_id_en argument, corresponding to CWE-74 and CWE-77. The issue is remotely reachable and carries a CVSS 4.0 score of 5.3.

An authenticated remote attacker can supply a crafted POST request to execute arbitrary commands on the device, resulting in limited impacts to confidentiality, integrity, and availability. The exploit has been publicly disclosed via a detailed proof-of-concept and does not require user interaction.

No vendor patch or mitigation guidance is available; the vendor was notified prior to disclosure but provided no response. Public references include a GitHub repository containing the technical details along with VulDB entries tracking the issue.

The associated EPSS score remains flat at 0.0195 with no material increase since publication, and no confirmed in-the-wild exploitation has been reported.

OWASP Top 10 for Web (2025)

A05:2025 Injection

EU & UK References

Vulnerability Data

A vulnerability was found in Linksys FGW3000-AH and FGW3000-HK up to 1.0.17.000000 and classified as critical. Affected by this issue is the function sub_4153FC of the file /cgi-bin/sysconf.cgi of the component HTTP POST Request Handler. The manipulation of the argument…

more

supplicant_rnd_id_en leads to command injection. The attack may be launched remotely. The exploit has been disclosed to the public and may be used. The vendor was contacted early about this disclosure but did not respond in any way.

CWE(s)
CWE-74CWE-77

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.
attack.mitre.org →
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.
attack.mitre.org →
T1221 Template Injection Stealth
Adversaries may create or modify references in user document templates to conceal malicious code or force authentication attempts.
attack.mitre.org →
T1659 Content Injection Initial Access
Adversaries may gain access and continuously communicate with victims by injecting malicious content into systems through online network traffic.
attack.mitre.org →
T1674 Input Injection Execution
Adversaries may simulate keystrokes on a victim’s computer by various means to perform any type of action on behalf of the user, such as launching the command interpreter using keyboard shortcuts, typing an inline script to be executed,…
attack.mitre.org →
T1059.001 PowerShell Execution
Adversaries may abuse PowerShell commands and scripts for execution.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2025-5000Same product: Linksys Fgw3000-Ah
CVE-2025-5438Same vendor: Linksys
CVE-2024-57539Same vendor: Linksys
CVE-2025-29228Same vendor: Linksys
CVE-2023-31740Same vendor: Linksys
CVE-2025-45489Same vendor: Linksys
CVE-2024-48286Same vendor: Linksys
CVE-2023-31741Same vendor: Linksys
CVE-2025-45488Same vendor: Linksys
CVE-2024-57223Same vendor: Linksys

Affected Assets

linksys
fgw3000-ah firmware
≤ 1.0.17.000000
linksys
fgw3000-hk firmware
≤ 1.0.17.000000

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)
  • V1.2.1
  • V1.2.3
  • V1.2.5
  • V1.2.8

Mitigating Controls (NIST 800-53 r5) AI

SA-11 Developer Testing and Evaluation good match

Developer testing and evaluation can discover command-construction flaws before deployment.

SI-10 Information Input Validation good match

SI-10 directly requires validation of information inputs to reject malformed or special-element content before it reaches downstream parsers.

SA-8 Security and Privacy Engineering Principles partial match

Secure engineering principles include proper neutralization and safe command construction practices.

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

Secure SDLC practices directly require input validation and output encoding that prevent injection flaws.

DE.CM-09 partial match
prevents

Runtime monitoring of software and data can detect anomalous command execution resulting from injection.

ID.RA-01 partial match
prevents

Identifying recorded vulnerabilities enables remediation of command-injection flaws before exploitation.

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.

A.8.28 Secure coding mostly match
prevents

Secure coding standards require proper escaping and parameterization of commands, directly eliminating CWE-77.

A.8.29 Security testing in development and acceptance mostly match
finds

Security testing in development catches injection vulnerabilities before release.

A.8.15 Logging partial match
finds

Logging supports detection of injection attempts but does not prevent the weakness.

A.8.16 Monitoring activities partial match
finds

Monitoring activities can identify active injection attacks after they occur.

A.8.25 Secure development life cycle partial match
prevents

Secure development life cycle mandates input validation and output encoding that directly prevent injection flaws.

A.8.26 Application security requirements partial match
prevents

Application security requirements explicitly call for controls against injection attacks in software design.

References