CVE-2023-30847: high-severity vulnerability in h2o
H2O vulnerable to read from uninitialized pointer in the reverse proxy handler
Published · Updated
E-mail alert when it lands in KEV, gets a public PoC or its score goes up.
21Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 8.2epss 0.9%
H2O is an HTTP server. In versions 2.3.0-beta2 and prior, when the reverse proxy handler tries to processes a certain type of invalid HTTP request, it tries to build an upstream URL by reading from uninitialized pointer. This behavior can lead to crashes or leak of information to back end HTTP servers. Pull request number 3229 fixes the issue. The pull request has been merged to the `master` branch in commit f010336. Users should upgrade to commit f010336 or later.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H
Affected products
h2o · h2oRelated CVEs — h2o
In the same product, most dangerous first.
CVE-2021-43848HIGHUnititialized memory access in h2oEPSS 2.7%CVE-2023-50247LOWh2o QUIC state exhaustion DoSEPSS 0.9%CVE-2024-45403LOWH2O assertion failure when HTTP/3 requests are cancelledEPSS 0.7%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%