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.
CVE Status: Modified
Attribute | Value |
---|---|
Attack Complexity | LOW |
Attack Vector | NETWORK |
Availability Impact | HIGH |
Base Score | 7.5 |
Base Severity | HIGH |
Confidentiality Impact | NONE |
Integrity Impact | NONE |
Privileges Required | NONE |
Scope | UNCHANGED |
User Interaction | NONE |
Vector String | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
Exploitability Score | 3.9 |
Impact Score | 3.6 |
Source | [email protected] |
Type | Primary |