{"id":"DEBIAN-CVE-2026-44452","details":"h2o is an HTTP server with support for HTTP/1.x, HTTP/2 and HTTP/3. Prior to commit 8dc37cb, when h2o receives a ClientHello message over TLS or QUIC and it contains a zero-length SNI extension, the h2o server runs over the zero-length hostname while trying to copy the hostname, assuming that it is NULL-terminated. This is a potential denial-of-service attack vector in sense that it might trigger segmentation violation. This issue has been fixed by commit 8dc37cb.","modified":"2026-09-14T17:03:13.223427586Z","published":"2026-07-16T23:16:17.280Z","upstream":["CVE-2026-44452"],"references":[{"type":"ADVISORY","url":"https://security-tracker.debian.org/tracker/CVE-2026-44452"}],"affected":[{"package":{"name":"h2o","ecosystem":"Debian:12","purl":"pkg:deb/debian/h2o?arch=source&distro=bookworm"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.2.5+dfsg2-10","2.2.5+dfsg2-11","2.2.5+dfsg2-7","2.2.5+dfsg2-8","2.2.5+dfsg2-8.1","2.2.5+dfsg2-8.1~exp1","2.2.5+dfsg2-9"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-44452.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H"}]}