CVE-2026-44452
5.9
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Summary
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.
Affected Software
| Vendor | Product | Version Range | Status |
|---|---|---|---|
| h2o | h2o | < 8dc37cb | affected |
Weaknesses
- CWE-125: CWE-125: Out-of-bounds Read
- CWE-170: CWE-170: Improper Null Termination
References
- https://github.com/h2o/h2o/security/advisories/GHSA-w68q-rqwx-7wvq
- https://github.com/h2o/h2o/commit/8dc37cb1e6171f7f772667618ea440696fed82c3
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