CVE-2024-45403: low-severity vulnerability in h2o
H2O assertion failure when HTTP/3 requests are cancelled
Published
E-mail alert when it lands in KEV, gets a public PoC or its score goes up.
8Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 3.7epss 0.7%
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:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L
Affected products
h2o · h2oRelated CVEs — h2o
In the same product, most dangerous first.
CVE-2021-43848HIGHUnititialized memory access in h2oEPSS 2.7%CVE-2023-30847HIGHH2O vulnerable to read from uninitialized pointer in the reverse proxy handlerEPSS 0.9%CVE-2023-50247LOWh2o QUIC state exhaustion DoSEPSS 0.9%CVE-2026-54340HIGHh2o has HTTP/2 state amplificationEPSS 0.5%CVE-2026-44453HIGHh2o is vulnerable to musl libc stack overflowEPSS 0.5%CVE-2026-55213HIGHh2o: musl libc stack overflow (QPACK)EPSS 0.5%