Cyber Resilience

CVE-2025-55848

Command Injection in Dlink Dir-823X Firmware 250416

Public PoCCommand Injection
Published
26 September 2025
Modified
09 March 2026
Patch / advisory
View advisory
CVSS Score v3.1 8.8
Click a component to see what it means
Raw vectorCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.0038 31th percentile
Risk Priority 63 floored blend · peak EPSS

Summary

CVE-2025-55848 is a high-severity Command Injection (CWE-77) vulnerability in Dlink Dir-823X Firmware. Its CVSS base score is 8.8 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Command and Scripting Interpreter (T1059); ranked at the 31th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

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-2025-55848 is a remote code execution (RCE) vulnerability discovered in the firmware version 20250416 of the D-Link DIR-823 router. The issue resides in the set_cassword settings interface, where the http_casswd parameter fails to properly filter the '&' character. This flaw enables attackers to inject arbitrary commands, such as reverse connection commands, leading to command injection as documented under CWE-77. The vulnerability carries a CVSS v3.1 base score of 8.8, reflecting its high severity.

Attackers on an adjacent network (AV:A) can exploit this vulnerability with low complexity (AC:L), requiring no privileges (PR:N) or user interaction (UI:N). Successful exploitation grants high impacts on confidentiality, integrity, and availability (C:H/I:H/A:H), allowing full RCE on the affected device within the local network segment, such as via a malicious HTTP request to the vulnerable endpoint.

For mitigation details, security practitioners should refer to the D-Link security bulletin at https://www.dlink.com/en/security-bulletin/ and the technical analysis including proof-of-concept at https://github.com/meigui637/iot_zone/blob/main/%E5%91%BD%E4%BB%A4%E6%89%A7%E8%A1%8C%E6%BC%8F%E6%B4%9E.md. Updating to a patched firmware version, if available, is recommended alongside network segmentation to limit adjacent access.

OWASP Top 10 for Web (2025)

A05:2025 Injection

EU & UK References

Vulnerability Data

An issue was discovered in DIR-823 firmware 20250416. There is an RCE vulnerability in the set_cassword settings interface, as the http_casswd parameter is not filtered by '&'to allow injection of reverse connection commands.

CWE(s)
CWE-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 →
T1059.001 PowerShell Execution
Adversaries may abuse PowerShell commands and scripts for execution.
attack.mitre.org →
T1059.003 Windows Command Shell Execution
Adversaries may abuse the Windows command shell for execution.
attack.mitre.org →
T1059.004 Unix Shell Execution
Adversaries may abuse Unix shell commands and scripts for execution.
attack.mitre.org →
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 →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2025-29635Same product: Dlink Dir-823X
CVE-2026-1544Same product: Dlink Dir-823X
CVE-2026-2129Same product: Dlink Dir-823X
CVE-2026-2120Same product: Dlink Dir-823X
CVE-2026-2175Same product: Dlink Dir-823X
CVE-2026-2063Same product: Dlink Dir-823X
CVE-2026-2084Same product: Dlink Dir-823X
CVE-2026-2157Same product: Dlink Dir-823X
CVE-2026-2143Same product: Dlink Dir-823X
CVE-2026-2155Same product: Dlink Dir-823X

Affected Assets

dlink
dir-823x firmware
250416

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)
  • V1.2.3
  • V1.2.5
  • V1.2.8
  • V1.2.9

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

Input validation directly stops construction of commands from untrusted data containing special elements.

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 neutralization that prevent command injection.

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 command-injection vulnerabilities before release.

A.8.25 Secure development life cycle partial match
prevents

Secure development life cycle mandates input validation and command construction practices that directly prevent command injection.

A.8.26 Application security requirements partial match
prevents

Application security requirements explicitly call for controls against injection flaws including command injection.

A.8.27 Secure system architecture and engineering principles partial match
prevents

Secure architecture principles reduce the attack surface but do not prescribe the specific neutralization techniques needed.

A.8.31 Separation of development, test and production environments none match
none

Environment separation limits the blast radius of an exploited command injection but does not prevent the flaw itself.

References