CVE-2026-3841

Authenticated command execution via unsanitized Telnet CLI input

Published Mar 12, 2026 · Updated Mar 12, 2026

OS command injection in TP-Link TL-MR6400 v5.3 before 1.9.0 Build 260108 allows remote authenticated users to execute system commands. The Telnet CLI passes insufficiently sanitized data from specific CLI operations into an operating-system command context. Adjacent-network access and elevated router privileges are required; successful commands can compromise the device's data and operation.

CVSS severity8.5
High
EPSS probability1.77%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

OS command injection in TP-Link TL-MR6400 v5.3 before 1.9.0 Build 260108 allows remote authenticated users to execute system commands. The Telnet CLI passes insufficiently sanitized data from specific CLI operations into an operating-system command context. Adjacent-network access and elevated router privileges are required; successful commands can compromise the device's data and operation.

The record

CVE
CVE-2026-3841
Published
Mar 12, 2026
Updated
Mar 12, 2026
Vendor
TP-Link Systems Inc.
Product
TL-MR6400
Classifications
CWE-78, T1059
Attack vector
adjacent
Privileges
admin

Timeline

How it unfolded

  1. Mar 12, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 12, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <1.9.0 Build 260108

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesadmin

What is affected?

TP-Link Systems Inc. · TL-MR6400version=0 <1.9.0 Build 260108

Published CVSS scores

8.5TP-Link Systems Inc.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
8.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectoradjacent
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-78Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
T1059Command and Scripting Interpreter

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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