CVE-2020-26759: Buffer Overflow in clickhouse-driver
Summary
CVE-2020-26759: clickhouse-driver before 0.1.5 allows a malicious clickhouse server to trigger a crash or execute arbitrary code (on a database client) via a crafted server response, due to a buffer overflow. Affects clickhouse-driver across 3 version ranges.
< 0.1.5
< 3e990547e064b8fca916b23a0f7d6fe8c63c7f6b
< d708ed548e1d6f254ba81a21de8ba543a53b5598
Fixed in d708ed548e1d6f254ba81a21de8ba543a53b5598. How to fix ↓
Also tracked for
- clickhouse · Bitnami
- python-clickhouse-driver · Debian:11
The same CVE-2020-26759 is tracked separately for each ecosystem and vendor. Its fix information is the same; the package and affected versions differ.
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Background
clickhouse-driver is a Python package that provides a client library for connecting to ClickHouse, an open-source column-oriented database management system. It allows users to interact with ClickHouse databases and execute queries. However, versions prior to 0.1.5 of clickhouse-driver are vulnerable to a buffer overflow.
Vulnerability Detail
The vulnerability (CVE-2020-26759) in clickhouse-driver allows a malicious ClickHouse server to trigger a crash or execute arbitrary code on a database client. This can be achieved by sending a crafted server response that exploits a buffer overflow. The buffer overflow occurs due to improper handling of server responses by the client library. An attacker could potentially exploit this vulnerability to compromise the integrity and confidentiality of the client system.
How To Fix
Latest published version: 0.2.11 as of 22 Oct 2026
pip install --upgrade "clickhouse-driver==0.2.11"Upgrading to it may include breaking changes; the version below is the minimum fixed release for this vulnerability.
If you need the minimum change
d708ed548e1d6f254ba81a21de8ba543a53b5598
This is the first release that contains the fix.
pip install --upgrade "clickhouse-driver==d708ed548e1d6f254ba81a21de8ba543a53b5598"Tip — Not sure which version your app runs? Vulert can match this fix to it. Scan free →
Workaround
There is no known workaround for this vulnerability. It is essential to update to the patched version of clickhouse-driver to ensure the security of the client system.
Conclusion
The vulnerability (CVE-2020-26759) in clickhouse-driver allows a malicious ClickHouse server to trigger a crash or execute arbitrary code on a database client. It is crucial to update clickhouse-driver to version 0.1.5 or later to mitigate this vulnerability. For further support on vulnerability remediation, please contact DevNack.com.
See every vulnerability recorded for clickhouse-driver →
FAQ
clickhouse-driver is a Python package that provides a client library for connecting to ClickHouse databases.
This vulnerability allows a malicious ClickHouse server to crash the client or execute arbitrary code on the client system.
To fix this vulnerability, update clickhouse-driver to version 0.1.5 or later.
No, there is no known workaround. Updating to the patched version is necessary.
You can find more information about this vulnerability in the official advisory: https://github.com/pypa/advisory-database/blob/main/vulns/clickhouse-driver/PYSEC-2021-61.yaml
