CVE-2024-45403
highpriority · track · 30EPSS 0.007 · 51 %ileEUUSEPSS · scored 2026-10-28
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
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · low–high · 3.7–7.5
ssvc
A stakeholder decision — act, attend, or track — from exploitation and impact.
weaknesses
The CWE weakness classes this flaw belongs to.
affected products (2)
Products and version ranges known to be affected.
also known as (2)
Other names and identifiers for this entity.
sources
Which sources assert this record, and when.
references (13)
External citations — patches, advisories, analysis.
- https://cxsecurity.com/cveshow/CVE-2024-45403/cnnvd
- https://github.com/h2o/h2o/commit/16b13eee8ad7895b4fe3fcbcabee53bd52782562cnnvd
- https://github.com/h2o/h2o/commit/1ed32b23f999acf0c5029f09c8525f93eb1d354ccnnvd
- https://github.com/h2o/h2o/security/advisories/GHSA-4xp5-3jhc-3m92cnnvd
- https://h2o.examp1e.net/configure/cnnvd
- https://github.com/h2o/h2o/commit/16b13eee8ad7895b4fe3fcbcabee53bd52782562enisa_euvd
- https://github.com/h2o/h2o/commit/1ed32b23f999acf0c5029f09c8525f93eb1d354cenisa_euvd
- https://github.com/h2o/h2o/security/advisories/GHSA-4xp5-3jhc-3m92enisa_euvd
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