CVE-2021-42387

HIGH
8.1
CVSS Score
Published: March 14, 2022 at 12:00 AM UTC
Updated: June 17, 2026 at 04:09 AM UTC
3 products affected across 3 vendorsDebian LinuxClickHouseClickhouse

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Severity
HIGH8.1
Exploit prediction
EPSS 2%

Description

Heap out-of-bounds read in Clickhouse's LZ4 compression codec when parsing a malicious query. As part of the LZ4::decompressImpl() loop, a 16-bit unsigned user-supplied value ('offset') is read from the compressed data. The offset is later used in the length of a copy operation, without checking the upper bounds of the source of the copy operation.

Affected

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

v < 21.10.2.15
Affected range stops below 21.10.2.15, so it looks safe — our inference, not a vendor statement
v < 21.10.2.15-stable
Affected range stops below 21.10.2.15-stable, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

CVSS

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

Quick Info

StatusMODIFIED
CWE
CWE-125

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