Is CVE-2024-45403 actively exploited?

No active exploitation of CVE-2024-45403 has been confirmed so far. Continue monitoring, as exploit status can change.

Can CVE-2024-45403 be exploited remotely?

Yes. CVE-2024-45403 is exploitable remotely over the network (CVSS attack vector: Network).

What is the CVSS score of CVE-2024-45403?

CVE-2024-45403 has a CVSS score of 7.5 (HIGH).

HOME VULNERABILITIESCVE-2024-45403

HIGH

CVE-2024-45403

CWE-617Published: October 11, 2024· Updated: Jun 17, 2026

7.5

CVSS v3.1

Official Description

h2o is an HTTP server with support for HTTP/1.x, HTTP/2 and HTTP/3. When h2o is configured as a reverse proxy and HTTP/3 requests are cancelled by the client, h2o might crash due to an assertion failure. The crash can be exploited by an attacker to mount a Denial-of-Service attack. By default, the h2o standalone server automatically restarts, minimizing the impact. However, HTTP requests that were served concurrently will still be disrupted. The vulnerability has been addressed in commit 1ed32b2. Users may disable the use of HTTP/3 to mitigate the issue.

NVD Source

Technical Analysis

CVE-2024-45403 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

A successful exploit results in availability disruption (denial of service), with a CVSS base score of 7.5.