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CVE-2021-42387

HIGH severity · CVSS 8.1 · Out-of-bounds read
8.1CVSS HIGH

Summary

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.

Impact & exploitability

Attack vectorNetwork
Attack complexityLow
Privileges requiredLow
User interactionNone
Confidentiality impactHigh
Integrity impactNone
Availability impactHigh
Exploit probability (EPSS)2%

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H

Affected products we track (1)

Recommendation

Apply the vendor fix promptly. Open any affected product above for its exact safe version.