CVE-2026-81664: Missing Authentication for Critical Function in openfaas faas
Description
A missing authentication vulnerability in OpenFaaS faas gateway versions 0.27.11 allows unauthenticated access to the /system/telemetry endpoint. This endpoint was introduced in version 0.27.11 but was not properly wrapped with basic authentication until version 0.27.14. As a result, any client able to reach the gateway port can access telemetry data without credentials, potentially exposing resource and invocation metrics or cluster state information depending on the provider configuration.
CVSS v4.0
Score 6.9medium
Affected software
openfaas
faas
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
OpenFaaS faas gateway versions 0.27.11 through before 0.27.14 have a missing authentication issue on the /system/telemetry endpoint. While basic_auth is enabled and applied to other administrative /system/* routes, the TelemetryHandler was omitted from the authentication wrapper between versions 0.27.11 and 0.27.14. This allows unauthenticated clients to access telemetry data forwarded by the provider, which may include resource usage metrics for faasd or cluster state for faas-netes. The vulnerability has a CVSS 4.0 base score of 6.9, indicating medium severity.
Potential Impact
Unauthenticated attackers can access telemetry data from the /system/telemetry endpoint on affected OpenFaaS gateways. The exposed data depends on the telemetry provider and may include sensitive operational metrics or cluster state information. This could aid attackers in reconnaissance but does not allow direct control or modification of the system.
Mitigation Recommendations
No official patch or fix is currently documented. The vulnerability was fixed by adding authentication wrapping to the TelemetryHandler in version 0.27.14. Users should upgrade to version 0.27.14 or later to remediate this issue. Until then, restricting network access to the gateway port can reduce exposure.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- VulnCheck
- Date Reserved
- 2026-08-27T10:36:58.425Z
- Cvss Version
- 4.0
- State
- PUBLISHED
Threat ID: 6a906bb2acd9273b4983a18a
Added to database: 08/27/2026, 16:54:10 UTC
Last enriched: 09/07/2026, 15:42:14 UTC
Last updated: 10/11/2026, 18:48:22 UTC
Views: 87
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