CVE-2023-30847Network attack vector

Crash or memory disclosure via ignored authority rejection

Published Apr 27, 2023 · Updated Jan 30, 2025

Uninitialized-pointer access in H2O 2.3.0-beta2 and earlier allows remote attackers to crash the server or leak memory to backends. In h2o__proxy_process_request, a rejected request authority leaves target_buf uninitialized because the h2o_url_init result is ignored. The request must reach an HTTP/1 reverse-proxy handler; released non-beta versions through 2.2.6 are unaffected, and impact is limited to a process crash or memory sent upstream.

CVSS severity8.2
High
EPSS probability0.90%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Uninitialized-pointer access in H2O 2.3.0-beta2 and earlier allows remote attackers to crash the server or leak memory to backends. In h2o__proxy_process_request, a rejected request authority leaves target_buf uninitialized because the h2o_url_init result is ignored. The request must reach an HTTP/1 reverse-proxy handler; released non-beta versions through 2.2.6 are unaffected, and impact is limited to a process crash or memory sent upstream.

The record

CVE
CVE-2023-30847
Published
Apr 27, 2023
Updated
Jan 30, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-824, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 27, 2023CVE publishedPublication date reported by the CVE source.
  2. Jan 30, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

8.2GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-824Access of Uninitialized Pointer
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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