#VU35171 Resource exhaustion in envoy - CVE-2019-15226
Published: October 9, 2019 / Updated: August 8, 2020
Vulnerability identifier: #VU35171
Vulnerability risk: Medium
CVSSv4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: CVE-2019-15226
CWE-ID: CWE-400
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerable software:
envoy
envoy
Software vendor:
Cloud Native Computing Foundation
Cloud Native Computing Foundation
Description
The vulnerability allows a remote non-authenticated attacker to perform a denial of service (DoS) attack.
Upon receiving each incoming request header data, Envoy will iterate over existing request headers to verify that the total size of the headers stays below a maximum limit. The implementation in versions 1.10.0 through 1.11.1 for HTTP/1.x traffic and all versions of Envoy for HTTP/2 traffic had O(n^2) performance characteristics. A remote attacker may craft a request that stays below the maximum request header size but consists of many thousands of small headers to consume CPU and result in a denial-of-service attack.
Remediation
Install update from vendor's website.