CVE-2026-11410: TP-Link TL-WR940N v6 Authenticated Command Injection – Patch Now

Technical summary

CVE-2026-11410 is an authenticated OS command injection vulnerability (CWE-78) in the BigPond Cable (BPA) WAN configuration module of TP-Link TL-WR940N v6. The flaw stems from insufficient input validation and sanitization of user-supplied parameters. An authenticated attacker can craft malicious input containing shell metacharacters to break out of the intended command context and execute arbitrary system commands. The vulnerability carries a CVSS 3.1 score of 7.2 (HIGH) with a network-accessible attack vector, low attack complexity, and high privileges required. Impact is complete—confidentiality, integrity, and availability are all fully compromised.

Business impact

Compromise of a TL-WR940N v6 router gives an attacker control over network traffic, potential lateral movement into connected systems, and ability to manipulate or exfiltrate data. In business environments, this translates to loss of network perimeter integrity, possible man-in-the-middle attack enablement, and supply-chain trust degradation if these routers are deployed at customer sites or branch offices. The authentication requirement limits exposure to insider threats and compromised administrative accounts—a meaningful but incomplete mitigation.

Affected systems

TP-Link TL-WR940N v6 routers running vulnerable firmware are in scope. The specific affected firmware versions should be verified against TP-Link's advisory. Organizations using this router model, particularly in Australia and regions served by BigPond Cable, are at highest risk. Check your device firmware version via the administrative web interface or SSH console.

Exploitability

Exploitation requires pre-existing administrative credentials to the router's web interface or SSH access. This authentication gate significantly reduces real-world attack surface compared to unauthenticated vulnerabilities. However, compromised admin credentials—whether through phishing, credential reuse, or prior lateral movement—are not uncommon, making this a practical risk once an attacker gains initial foothold into a network segment. No public exploit code is known to be available, and the vulnerability is not listed on CISA's KEV catalog.

Remediation

Immediately apply the latest firmware update from TP-Link for the TL-WR940N v6. Verify the firmware version in the device's administrative settings and download patches directly from TP-Link's official support portal. Pending patching, enforce strong, unique administrative passwords, disable remote management access if not required, and restrict administrative access to trusted networks only. Consider segmenting these devices on isolated network VLANs to limit blast radius.

Patch guidance

Visit TP-Link's official support website and locate the TL-WR940N v6 product page. Download the latest available firmware build for your region (particularly for BigPond/Australian variants). The patch information should detail the specific firmware version that closes this vulnerability; verify the release notes confirm CVE-2026-11410 remediation. Deploy the patch in a maintenance window after backing up current router configuration. Test basic connectivity and WAN functionality post-patch to confirm stability.

Detection guidance

Monitor router administrative access logs for unusual login patterns, especially from non-standard IP addresses or at irregular times. Search logs for command injection indicators—look for input containing backticks, dollar-parentheses syntax, semicolons, or pipes ('|', ';', '`', '$()') in WAN configuration parameters. Network-based detection is limited since the attack occurs post-authentication; focus on monitoring administrative console activity and filesystem changes on the router. If your security tools can capture HTTP POST payloads to the WAN config module, inspect for shell metacharacters.

Why prioritize this

This vulnerability merits rapid but not emergency patching. The HIGH CVSS score and complete impact scope (CIA all compromised) demand timely remediation, but the authentication requirement limits your immediate exposure. Prioritize patches for routers exposed to untrusted networks, those supporting critical business functions, or devices in high-risk segments. Tier patching: first, internet-facing administrative interfaces; second, branch office and customer-facing deployments; third, internal-only lab or non-critical routers.

Risk score, explained

The CVSS 3.1 score of 7.2 reflects the combination of high impact (all three security properties fully compromised), low attack complexity, and network accessibility, tempered significantly by the requirement for high privileges (administrative access). The score is appropriate: this is a serious post-compromise escalation vector that a security leader should address promptly but not at the expense of unpatched unauthenticated RCE flaws elsewhere in their environment.

Frequently asked questions