Raw vector
CVSS:4.0/AV:A/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/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:XCVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.
Summary
CVE-2026-3841 is a high-severity OS Command Injection (CWE-78) vulnerability in Tp-Link Tl-Mr6400 Firmware. Its CVSS base score is 8.5 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Command and Scripting Interpreter (T1059); ranked in the top 23% 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 exists in the Telnet command-line interface of the TP-Link TL-MR6400 v5.3 router. The flaw stems from insufficient sanitization of data during specific CLI operations and is tracked under CWE-78. It carries a CVSS 4.0 score of 8.5 with an attack vector of adjacent network and high privileges required.
An authenticated attacker who already possesses elevated privileges on the device can supply crafted input to execute arbitrary system commands. Successful exploitation grants full control of the router, resulting in loss of confidentiality, integrity, and availability of the device and any connected network resources.
TP-Link publishes updated firmware for the TL-MR6400 v5.3 series and related support documentation at the referenced URLs. The current EPSS score of 0.0074 with a recorded peak of 0.0102 reflects limited observed exploitation interest.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-11655
Vulnerability Data
A command injection vulnerability has been identified in the Telnet command-line interface (CLI) of TP-Link TL-MR6400 v5.3. This issue is caused by insufficient sanitization of data processed during specific CLI operations. An authenticated attacker with elevated privileges may be able…
more
to execute arbitrary system commands. Successful exploitation may lead to full device compromise, including potential loss of confidentiality, integrity, and availability.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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V1.2.5V1.2.8V15.2.5
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'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.
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.
Security testing and code review target insecure use of operating-system command interfaces, catching command-injection flaws introduced during development.