The Envoy security team today [announced] the availability of Envoy 1.9.1 to address two high-risk vulnerabilities related to header values and HTTP URL paths.
We also released the GetEnvoy build of Envoy 1.9.1 and the latest master build that fixes the vulnerability. Users are encouraged to upgrade to 1.9.1 or latest master build to address the following CVEs:
- CVE-2019-9900: When parsing HTTP/1.x header values, Envoy 1.9 and before does not reject embedded zero characters (NUL, ASCII 0x0). This allows remote attackers crafting header values containing embedded NUL characters to potentially bypass header matching rules, gaining access to unauthorized resources.
- CVE-2019-9901: Envoy does not normalize HTTP URL paths in Envoy 1.9 and before. 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.