OpenFaaS up to 0.27.13 Authentication gateway/main.go auth.DecorateWithBasicAuth improper authorization

Summaryinfo

A vulnerability described as problematic has been identified in OpenFaaS up to 0.27.13. This issue affects the function auth.DecorateWithBasicAuth of the file gateway/main.go of the component Authentication Handler. Executing a manipulation can lead to improper authorization. This vulnerability appears as CVE-2026-81664. The attack may be performed from remote. There is no available exploit.

Detailsinfo

A vulnerability was found in OpenFaaS up to 0.27.13. It has been declared as problematic. This vulnerability affects the function auth.DecorateWithBasicAuth of the file gateway/main.go of the component Authentication Handler. The manipulation with an unknown input leads to a improper authorization vulnerability. The CWE definition for the vulnerability is CWE-285. The product does not perform or incorrectly performs an authorization check when an actor attempts to access a resource or perform an action. As an impact it is known to affect confidentiality. CVE summarizes:

The OpenFaaS gateway registers GET /system/telemetry in gateway/main.go and, when basic_auth is enabled, wraps each administrative /system/* handler in auth.DecorateWithBasicAuth. TelemetryHandler was left out of that wrap block from 0.27.11, which introduced the route, until 0.27.14, which added it. On an affected gateway the route therefore reaches the forwarding proxy with no credential check and returns whatever the configured provider serves for /system/telemetry, so any client that can reach the gateway port can read the provider's telemetry regardless of the basic_auth setting. The exposed content depends on the provider, and covers resource and invocation metrics for faasd and pod or cluster state for faas-netes.

The advisory is shared for download at github.com. This vulnerability was named CVE-2026-81664 since 08/27/2026. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. There are known technical details, but no exploit is available. The MITRE ATT&CK project declares the attack technique as T1548.002.

Upgrading to version 0.27.14 eliminates this vulnerability.

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Productinfo

Name

• OpenFaaS

Version

• 0.27.0
• 0.27.1
• 0.27.2
• 0.27.3
• 0.27.4
• 0.27.5
• 0.27.6
• 0.27.7
• 0.27.8
• 0.27.9
• 0.27.10
• 0.27.11
• 0.27.12
• 0.27.13

CPE 2.3info

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CPE 2.2info

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