cvedb.io
CVE-2021-39155
HIGH · CVSS 8.3
EPSS exploitation probability: 0%
Published 2021-08-24T23:15:07.093 · Last modified 2026-06-17T04:03:12.617

Summary

Istio is an open source platform for providing a uniform way to integrate microservices, manage traffic flow across microservices, enforce policies and aggregate telemetry data. According to [RFC 4343](https://datatracker.ietf.org/doc/html/rfc4343), Istio authorization policy should compare the hostname in the HTTP Host header in a case insensitive way, but currently the comparison is case sensitive. The proxy will route the request hostname in a case-insensitive way which means the authorization policy could be bypassed. As an example, the user may have an authorization policy that rejects request with hostname "httpbin.foo" for some source IPs, but the attacker can bypass this by sending the request with hostname "Httpbin.Foo". Patches are available in Istio 1.11.1, Istio 1.10.4 and Isti

Affected products

istio — istio

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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.