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CRITICAL severity

CVE-2020-26759 — clickhouse-driver

CRITICALFix: mymarilyn/clickhouse-driver@3e99054

CVE-2020-26759 is a critical-severity (CVSS 9.8) CWE-120 vulnerability in clickhouse-driver. A fix is available for clickhouse-driver — see the affected versions and patch details below.

Arbitrary code execution in clickhouse-driver

Also known asBIT-clickhouse-2020-26759GHSA-vgv5-cxvh-vfxhPYSEC-2021-61
Published
Updated
Affected
1 pkg
Patched
1 / 1
Exploits
None indexed
Exploitation data as of Oct 9, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗
2.7%probability of exploitation in next 30 days
Lower Risk+0.11%
Lower risk than most CVEs85th percentile — riskier than 85% of all scored CVEsHighest risk
2.06%2.57%3.09%3.61%3.1%2.7%Apr 26Aug 26Oct 26

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

CVE-2020-26759 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 385,738 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.

Real-World Exposure

1 pkg affected
🐍clickhouse-driver

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.

Description

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.

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
🐍PyPIclickhouse-driverall versions0.1.5pip install --upgrade 'clickhouse-driver==0.1.5'

Affected Products

1 product · 1 configurations
Application
clickhouse-driverclickhouse-driver_project
< 0.1.5
range

Detection & mitigation playbook

Open-source dependency

  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for clickhouse-driver, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update clickhouse-driver to 0.1.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2020-26759 is resolved across your whole dependency graph.

  3. Workarounds

    Constrain what reaches the vulnerable code: limit the size and shape of untrusted input, isolate the affected component in a sandboxed or least-privileged process, and enable the platform's memory-safety mitigations (ASLR, stack protector, hardened allocator) so an out-of-bounds access is more likely to fail closed than to be exploitable.

Frequently Asked Questions

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.
O3 Security · Impact-Aware SCA

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CVE-2020-26759: clickhouse-driver RCE — Fixed in 0.1.5