What’s Vulnerable › Vulnerabilities

CVE-2026-3841: Command Injection Vulnerability in Telnet CLI on TP-Link TL-MR6400

• Severity: high (CVSS 8.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.9% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-03-12 · updated 2026-06-17
• Weakness: CWE-78

Description

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 to execute arbitrary system commands. Successful exploitation may lead to full device compromise, including potential loss of confidentiality, integrity, and availability.

Affected products

• TP-Link Systems Inc. TL-MR6400 v5.3: before 1.9.0 — fixed in 1.9.0

How to fix

Upgrade to a fixed version: TP-Link Systems Inc. TL-MR6400 v5.3 1.9.0. Check the vendor advisory for mitigations.

References

• https://www.tp-link.com/en/support/download/tl-mr6400/v5.30/#Firmware
• https://www.tp-link.com/us/support/faq/5016/

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