CVE-2023-30847

H2O vulnerable to read from uninitialized pointer in the reverse proxy handler

HIGH
8.2
CVSS Score
Published: April 27, 2023 at 02:08 PM UTC
Updated: June 17, 2026 at 05:55 AM UTC
2 products affected across 2 vendorsH2OH2O

Using h2o by h2o?

Get instant alerts when new vulnerabilities affect h2o - before attackers find them.

Real-time alertsTrack your software stackFree plan available
Severity
HIGH8.2
Exploit prediction
EPSS 0.9%
SSVC
No known exploit

Description

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v ≤ 2.3.0-beta2

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

SSVC — Action Prioritization

SSVCNo known exploitAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

8.2HIGHGitHub_M
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
LOW
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-824

Get alerted

Stop reading CVE feeds looking for your own stack

Track the products you run and VulnTracker tells you when a new CVE affects them — with what is known about fixing it, and nothing about the rest.

Free plan, no card