Allocation of Resources Without Limits or Throttling 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-18016350
- published19 Jul 2026
- disclosed16 Jul 2026
Introduced: 16 Jul 2026
NewCVE-2026-44453 (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 6b5370d, h2o is vulnerable to a Denial of Service attack when calling alloca under certain conditions. When serving static files, h2o builds the file path on stack, by calling alloca. The maximum size of the memory allocated using alloca can be as huge as ~600KB, which exceeds the default pthread stack size used by musl libc (128KB). If the amount of memory allocated by alloca exceeds the stack size, the h2o server crashes with a segmentation fault, while it tries to touch the guard page. This issue has been fixed by commit 6b5370d.