CVE-2024-10549 Denial of Service by ReDOS in h2oai/h2o-3
An attacker can cause a denial of service in H2O-3 by sending simultaneous requests to the Parse endpoint, exhausting threads via ReDoS.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2024-10549?
CVE-2024-10549 is a high-severity denial of service vulnerability in h2oai/h2o-3, published on 20 Mar 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
A vulnerability in the `/3/Parse` endpoint of h2oai/h2o-3 version 3.46.0.1 allows for a denial of service (DoS) attack. The endpoint uses a user-specified string to construct a regular expression, which is then applied to another user-specified string. By sending multiple simultaneous requests, an attacker can exhaust all available threads, leading to a complete denial of service.
Weakness: CWE-1333
Which versions are affected by CVE-2024-10549?
5 open source packages ship an affected version, including h2o and ai.h2o:h2o-core. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
h2o PyPI | From 3.30.0.7 to 3.46.0.1 | None |
h2o PyPI | From 3.30.0.7 to 3.46.0.1 | None |
h2o PyPI | From 3.30.0.7 to 3.46.0.1 | None |
ai.h2o:h2o-core Maven | From 3.30.0.7 to 3.46.0.1 | None |
ai.h2o:h2o-core Maven | From 3.30.0.7 to 3.46.0.1 | None |
Products include H2o H2o.
How do I fix CVE-2024-10549?
No fix has been published for CVE-2024-10549 yet. Limit exposure of the affected software until one is available.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2024-10549 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2024-10549 exists.
Other vulnerabilities in h2oai/h2o-3
Sources
Also known as GHSA-wwr9-4gmr-xvq9, PYSEC-2026-1445.