h2o project reports: When h2o receives a TLS or QUIC ClientHello containing a zero-length SNI extension, it can overrun the zero-length hostname while copying it. This can trigger a segmentation fault and cause a denial of service.
Source: Mitre, NVD
Published: 2026-06-11
Base Score: 5
Vector: CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:P
Severity: Medium
Base Score: 7.5
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Severity: High
EPSS: 0.00052