What is CVE-2019-18657?

CVE-2019-18657 is a medium-severity vulnerability in Clickhouse, classified under Improper Neutralization of Special Elements in Output Used by a Downstream Component (Injection). CVSS score: 5.3/10. Published 2019-10-31.

How severe is CVE-2019-18657?

Medium severity. CVSS v3 base score is 5.3 out of 10.

Vulnerability in Clickhouse

CVE-2019-18657

ClickHouse before 19.13.5.44 allows HTTP header injection via the url table function.

Published 2019-10-31 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N.

EPSS exploit prediction

EPSS: 0.015 (72.6th percentile), scored 2026-09-29.

Low probability of exploitation in the next 30 days, but still tracked. 73rd percentile — 72.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.015 · newest: 0.015 · change: 0.000

Affected products

Clickhouse

Weakness classification (CWE)

CWE-74 — Improper Neutralization of Special Elements in Output Used by a Downstream Component (Injection)

References

github.com/ClickHouse/ClickHouse/pull/6466 (Third Party Advisory)
github.com/ClickHouse/ClickHouse/blob/master/CHANGELOG.md (Third Party Advisory)
github.com/ClickHouse/ClickHouse/pull/7526/files (Patch, Third Party Advisory)

Frequently asked questions

What is CVE-2019-18657?: CVE-2019-18657 is a medium-severity vulnerability in Clickhouse, classified under Improper Neutralization of Special Elements in Output Used by a Downstream Component (Injection). CVSS score: 5.3/10. Published 2019-10-31.
How severe is CVE-2019-18657?: Medium severity. CVSS v3 base score is 5.3 out of 10.