cvedb.io
CVE-2026-18248
CRITICAL · CVSS 9.1
EPSS exploitation probability: 0%
Published 2026-08-03T16:16:28.247 · Last modified 2026-08-03T16:16:28.247

Summary

@fastify/aws-lambda version 6.4.0 decorates each Fastify request with request.awsLambda.event and request.awsLambda.context, values that applications are documented to use for authorization decisions such as reading API Gateway authorizer claims. In the default configuration, the getter that populates this decoration reads the client-controlled x-apigateway-event and x-apigateway-context HTTP headers before falling back to the trusted internal request token, and those reserved headers are not stripped from the incoming event. An unauthenticated attacker who can set a single HTTP header can therefore forge the entire Lambda proxy event, including the authorizer context, and override the genuine one. This results in a full authentication and authorization bypass and privilege escalation for

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References

This product uses data from the NVD API but is not endorsed or certified by the NVD. Informational only; not professional security advice.