Description
h2o is an HTTP server with support for HTTP/1.x, HTTP/2 and HTTP/3. When an HTTP request using TLS/1.3 early data on top of TCP Fast Open or QUIC 0-RTT packets is received and the IP-address-based access control is used, the access control does not detect and prohibit HTTP requests conveyed by packets with a spoofed source address. This behavior allows attackers on the network to execute HTTP requests from addresses that are otherwise rejected by the address-based access control. The vulnerability has been addressed in commit 15ed15a. Users may disable the use of TCP FastOpen and QUIC to mitigate the issue.
Metrics
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:NWeakness enumeration
Affected software
No affected versions have been published.
Timeline
- Published
- Oct 11, 2024
- Last modified
- Jun 17, 2026
- NVD status
- Analyzed