AT&T Arris BGW210-700 up to 2.7.7 CGI /cgi-bin/*.ha missing authentication

Summaryinfo

A vulnerability described as very critical has been identified in AT&T Arris BGW210-700 up to 2.7.7. Affected is an unknown function of the file /cgi-bin/*.ha of the component CGI Handler. The manipulation results in missing authentication. This vulnerability is identified as CVE-2026-16771. The attack can be executed remotely. There is not any exploit available.

Detailsinfo

A vulnerability classified as very critical has been found in AT&T Arris BGW210-700 up to 2.7.7. Affected is an unknown code block of the file /cgi-bin/*.ha of the component CGI Handler. The manipulation with an unknown input leads to a missing authentication vulnerability. CWE is classifying the issue as CWE-306. The product does not perform any authentication for functionality that requires a provable user identity or consumes a significant amount of resources. This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

In firmware versions 2.7.7 and earlier, the Arris BGW210‑700 gateway fails to enforce any server‑side authentication on its /cgi-bin/*.ha management endpoints, relying solely on client‑side CSS/JavaScript gating that can be bypassed by any HTTP client. This allows unauthenticated attackers on the LAN to read sensitive configuration data, modify persistent device settings, or trigger backend diagnostic operations. The issue appears systemic across the CGI handler chain.

The advisory is shared for download at kb.cert.org. This vulnerability is traded as CVE-2026-16771 since 07/23/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 07/28/2026).

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

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Productinfo

Vendor

• AT&T

Name

• Arris BGW210-700

Version

• 2.7.0
• 2.7.1
• 2.7.2
• 2.7.3
• 2.7.4
• 2.7.5
• 2.7.6
• 2.7.7

License

• commercial

CPE 2.3info

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CPE 2.2info

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