What is CVE-2021-20217?

CVE-2021-20217 is a high-severity vulnerability in Privoxy, classified under Reachable Assertion. CVSS score: 7.5/10. Published 2021-03-25.

How severe is CVE-2021-20217?

High severity. CVSS v3 base score is 7.5 out of 10.

Is CVE-2021-20217 known to be exploited?

1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

Vulnerability in Privoxy

CVE-2021-20217

A flaw was found in Privoxy in versions before 3.0.31. An assertion failure triggered by a crafted CGI request may lead to denial of service. The highest threat from this vulnerability is to system availability.

Published 2021-03-25 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.014 (70.9th percentile), scored 2026-09-30.

Low probability of exploitation in the next 30 days, but still tracked. 71st percentile — 70.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.014 · newest: 0.014 · change: 0.000

Affected products

Privoxy
Privoxy — versions privoxy 3.0.31

Weakness classification (CWE)

CWE-617 — Reachable Assertion

Public proof-of-concept exploits

MegaManSec/privoxy

References

bugzilla.redhat.com/show_bug.cgi (Third Party Advisory, Issue Tracking)
security.gentoo.org/glsa/202107-16 (vendor-advisory, Third Party Advisory)

Frequently asked questions

What is CVE-2021-20217?: CVE-2021-20217 is a high-severity vulnerability in Privoxy, classified under Reachable Assertion. CVSS score: 7.5/10. Published 2021-03-25.
How severe is CVE-2021-20217?: High severity. CVSS v3 base score is 7.5 out of 10.
Is CVE-2021-20217 known to be exploited?: 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.