Cyber Resilience

CVE-2026-5030

Command Injection in Totolink Nr1800X Firmware 9.1.0u.6279_b20210910

Public PoCCommand Injection
Published
29 March 2026
Modified
30 March 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:P/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 0.025 84th percentile
Risk Priority 38 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-2026-5030 is a medium-severity Injection (CWE-74) vulnerability in Totolink Nr1800X Firmware. Its CVSS base score is 5.3 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Dynamic Linker Hijacking (T1574.006); ranked in the top 16% of CVEs by exploit likelihood; 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-2026-5030 is a command injection vulnerability affecting the Totolink NR1800X router on firmware version 9.1.0u.6279_B20210910. The issue resides in the NTPSyncWithHost function of the /cgi-bin/cstecgi.cgi file within the Telnet Service component, where manipulation of the host_time argument enables command injection. Published on 2026-03-29, it is associated with CWEs-74 and CWE-77 and carries a CVSS v3.1 base score of 6.3 (AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L).

The vulnerability can be exploited remotely by an attacker with low privileges (PR:L), requiring low attack complexity and no user interaction. Successful exploitation allows limited impacts on confidentiality, integrity, and availability through injected commands.

Advisories and additional details, including public exploit disclosure, are available via references such as VulDB entries (vuldb.com/vuln/353952), a proof-of-concept at a Notion site, and the vendor site at www.totolink.net. The exploit has been disclosed to the public and may be used.

OWASP Top 10 for Web (2025)

A05:2025 Injection

EU & UK References

Vulnerability Data

A vulnerability has been found in Totolink NR1800X 9.1.0u.6279_B20210910. This issue affects the function NTPSyncWithHost of the file /cgi-bin/cstecgi.cgi of the component Telnet Service. The manipulation of the argument host_time leads to command injection. The attack can be initiated remotely.…

more

The exploit has been disclosed to the public and may be used.

CWE(s)
CWE-74CWE-77

Related Threats

MITRE ATT&CK Enterprise Techniques

T1574.006 Dynamic Linker Hijacking Stealth
Adversaries may execute their own malicious payloads by hijacking environment variables the dynamic linker uses to load shared libraries.
attack.mitre.org →
T1059 Command and Scripting Interpreter Execution
Adversaries may abuse command and script interpreters to execute commands, scripts, or binaries.
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-2026-1326Same product: Totolink Nr1800X
CVE-2026-1327Same product: Totolink Nr1800X
CVE-2026-1150Same vendor: Totolink
CVE-2025-9935Same vendor: Totolink
CVE-2025-4729Same vendor: Totolink
CVE-2026-1149Same vendor: Totolink
CVE-2025-3249Same vendor: Totolink
CVE-2025-4851Same vendor: Totolink
CVE-2026-5104Same vendor: Totolink
CVE-2026-5176Same vendor: Totolink

Affected Assets

totolink
nr1800x firmware
9.1.0u.6279_b20210910

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.

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.

PR.PS-06 partial match
prevents

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

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.8.15 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.

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

Secure architecture principles reduce injection surfaces but do not prescribe specific neutralization techniques.

A.8.28 Secure coding partial match
prevents

Secure coding standards require proper neutralization of special elements, directly addressing CWE-74.

References