{"cve":"CVE-2024-45403","nvd":{"published":"2024-10-11T15:15:05.123","modified":"2026-06-17T07:54:08.843","status":"Analyzed","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.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","score":7.5},"cwes":["CWE-617"],"references":["https://github.com/h2o/h2o/commit/16b13eee8ad7895b4fe3fcbcabee53bd52782562","https://github.com/h2o/h2o/commit/1ed32b23f999acf0c5029f09c8525f93eb1d354c","https://github.com/h2o/h2o/security/advisories/GHSA-4xp5-3jhc-3m92","https://h2o.examp1e.net/configure/http3_directives.html"],"products":["dena:h2o"],"source":"nvd","synced_at":"2026-10-19T21:55:31.737901711+00:00"},"epss":{"cve":"CVE-2024-45403","score":0.00653,"percentile":0.513,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}