CVE-2020-11767

Public Exploit

Description

Istio through 1.5.1 and Envoy through 1.14.1 have a data-leak issue. If there is a TCP connection (negotiated with SNI over HTTPS) to *.example.com, a request for a domain concurrently configured explicitly (e.g., abc.example.com) is sent to the server(s) listening behind *.example.com. The outcome should instead be 421 Misdirected Request. Imagine a shared caching forward proxy re-using an HTTP/2 connection for a large subnet with many users. If a victim is interacting with abc.example.com, and a server (for abc.example.com) recycles the TCP connection to the forward proxy, the victim's browser may suddenly start sending sensitive data to a *.example.com server. This occurs because the forward proxy between the victim and the origin server reuses connections (which obeys the specification), but neither Istio nor Envoy corrects this by sending a 421 error. Similarly, this behavior voids the security model browsers have put in place between domains.

3.1

CVSS

Severity: Low

CVSS 3.1 •

CVSS 2.0 •

EPSS 0.03%

Third-Party Advisory chromium.org Third-Party Advisory github.com Third-Party Advisory github.com Third-Party Advisory github.com

Affected: n/a n/a

References

Link	Tags
https://bugs.chromium.org/p/chromium/issues/detail?id=954160#c5	third party advisory issue tracking
https://github.com/envoyproxy/envoy/issues/6767	third party advisory
https://github.com/istio/istio/issues/9429	third party advisory
https://github.com/istio/istio/issues/13589	third party advisory exploit

Frequently Asked Questions

What is the severity of CVE-2020-11767?: CVE-2020-11767 has been scored as a low severity vulnerability.
How to fix CVE-2020-11767?: To fix CVE-2020-11767, make sure you are using an up-to-date version of the affected component(s) by checking the vendor release notes. As for now, there are no other specific guidelines available.
Is CVE-2020-11767 being actively exploited in the wild?: It is possible that CVE-2020-11767 is being exploited or will be exploited in a near future based on public information. According to its EPSS score, there is a ~0% probability that this vulnerability will be exploited by malicious actors in the next 30 days.

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