Out-of-bounds Read Affecting h2o package, versions *
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
Do your applications use this vulnerable package?
In a few clicks we can analyze your entire application and see what components are vulnerable in your application, and suggest you quick fixes.
Test your applications- Snyk IDSNYK-ECHOLATEST-H2O-18016349
- published19 Jul 2026
- disclosed16 Jul 2026
Introduced: 16 Jul 2026
NewCVE-2026-44452 (opens in a new tab)How to fix?
There is no fixed version for Echo:latest h2o.
NVD Description
Note: Versions mentioned in the description apply only to the upstream h2o package and not the h2o package as distributed by Echo.
See How to fix? for Echo:latest relevant fixed versions and status.
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.