CVE-2023-47118Network attack vector

Unauthenticated server crash via T64 count underflow

Published Dec 20, 2023 · Updated Aug 2, 2024

Heap buffer overflow in affected ClickHouse Server releases allows remote attackers to crash the process with malformed T64-compressed data. CompressionCodecT64::decompressData decrements a zero full-block count for a declared tail before checking compressed and output element counts. The native interface exposes the crash path without authentication on port 9000 by default, while the HTTP path requires valid credentials.

CVSS severity7.0
High
EPSS probability0.46%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Heap buffer overflow in affected ClickHouse Server releases allows remote attackers to crash the process with malformed T64-compressed data. CompressionCodecT64::decompressData decrements a zero full-block count for a declared tail before checking compressed and output element counts. The native interface exposes the crash path without authentication on port 9000 by default, while the HTTP path requires valid credentials.

The record

CVE
CVE-2023-47118
Published
Dec 20, 2023
Updated
Aug 2, 2024
Vendor
ClickHouse
Product
ClickHouse
Classifications
CWE-122, CWE-787, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Dec 20, 2023CVE publishedPublication date reported by the CVE source.
  2. Aug 2, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 23.3.16.7-lts

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

ClickHouse · ClickHouseversion=< 23.3.16.7-lts

Published CVSS scores

9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
7.0GitHub CNACVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/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-122Heap-based Buffer Overflow
CWE-787Out-of-bounds Write
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

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo