What is CVE-2020-18703?

CVE-2020-18703 is a critical-severity vulnerability in Quokka Project, classified under Improper Restriction of XML External Entity Reference (XXE). CVSS score: 9.8/10. Published 2021-08-16.

How severe is CVE-2020-18703?

Critical severity. CVSS v3 base score is 9.8 out of 10.

XXE in Quokka Project

CVE-2020-18703

XML External Entities (XXE) in Quokka v0.4.0 allows remote attackers to execute arbitrary code via the component 'quokka/utils/atom.py'.

Vulnerability class: XXE (XML External Entity)

Published 2021-08-16 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.028 (85.8th percentile), scored 2026-10-02.

Low probability of exploitation in the next 30 days, but still tracked. 86th percentile — 85.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.028 · newest: 0.028 · change: 0.000

Affected products

Quokka Project — versions 0.4.0

Weakness classification (CWE)

CWE-611 — Improper Restriction of XML External Entity Reference (XXE)

References

github.com/rochacbruno/quokka/issues/676 (Exploit, Patch, Third Party Advisory)

Frequently asked questions

What is CVE-2020-18703?: CVE-2020-18703 is a critical-severity vulnerability in Quokka Project, classified under Improper Restriction of XML External Entity Reference (XXE). CVSS score: 9.8/10. Published 2021-08-16.
How severe is CVE-2020-18703?: Critical severity. CVSS v3 base score is 9.8 out of 10.