CVE-2019-9901: Critical severity envoy proxy vulnerability
A flaw was found in Envoy 1.9.0 and older. Envoy does not normalize HTTP URL paths. A remote attacker may craft a path with a relative path, e.g. something/../admin, to bypass access control, e.g. a block on /admin. A backend server could then interpret the unnormalized path and provide an attacker access beyond the scope provided for by the access control policy.
Upstream issue:
https://github.com/envoyproxy/envoy/issues/6435
References:
https://istio.io/blog/2019/announcing-1.1.2/
Other sources
Envoy 1.9.0 and before does not normalize HTTP URL paths. A remote attacker may craft a relative path, e.g., something/../admin, to bypass access control, e.g., a block on /admin. A backend server could then interpret the non-normalized path and provide an attacker access beyond the scope provided for by the access control policy.
Envoy 1.9.0 and before does not normalize HTTP URL paths. A remote attacker may craft a relative path, e.g., something/../admin, to bypass access control, e.g., a block on /admin. A backend server could then interpret the non-normalized path and provide an attacker access beyond the scope provided for by the access control policy.
— MITRE
Affected Software
Remediation
Event History
Frequently Asked Questions
What is the vulnerability ID for this vulnerability?
The vulnerability ID for this vulnerability is CVE-2019-9901.
What is the severity of CVE-2019-9901?
CVE-2019-9901 has a severity level of critical.
What software versions are affected by CVE-2019-9901?
Envoy 1.9.0 and versions before 1.9.0 are affected by CVE-2019-9901.
How can an attacker exploit CVE-2019-9901?
An attacker can exploit CVE-2019-9901 by crafting a relative path to bypass access control.
Where can I find more information about CVE-2019-9901?
You can find more information about CVE-2019-9901 at the following references: [github.com/envoyproxy/envoy/security/advisories/GHSA-xcx5-93pw-jw2w](https://github.com/envoyproxy/envoy/security/advisories/GHSA-xcx5-93pw-jw2w) and [nvd.nist.gov/vuln/detail/CVE-2019-9901](https://nvd.nist.gov/vuln/detail/CVE-2019-9901).