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Fencer Vulns
high 7.5

CVE-2021-20217 json

A flaw was found in Privoxy in versions before 3.0.31.

published 2021-03-25 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-7660

cvss
7.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.4%
EPSS 1.4% chance of exploitation in 30 days, percentile 72%
public exploits
0
none known

Summary

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.

Patch / fix

  • privoxy privoxy 3.0.31
  • privoxy Debian 14, Debian 13, Debian 12 3.0.31-1

debian advisories DEBIAN-CVE-2021-20217

  • privoxy Ubuntu 16.04 LTS 3.0.24-1ubuntu0.1
  • privoxy Ubuntu 18.04 LTS 3.0.26-5ubuntu0.1
  • privoxy Ubuntu 20.04 LTS 3.0.28-2ubuntu0.1
  • privoxy Ubuntu Pro 14.04 LTS 3.0.21-7+deb8u1ubuntu0.1~esm1

ubuntu advisories UBUNTU-CVE-2021-20217

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • privoxy openSUSE Tumbleweed 3.0.32-2.3
  • privoxy Package Hub 15 SP2 3.0.31-bp152.4.6.1
  • privoxy openSUSE Leap 15.2 3.0.31-lp152.3.6.1

opensuse advisories openSUSE-SU-2024:11193-1openSUSE-SU-2021:0279-1openSUSE-SU-2021:0265-1

  • privoxy Alpine 3.24, Alpine 3.23, Alpine 3.22 +10 more 3.0.31-r0

alpine advisories ALPINE-CVE-2021-20217

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • privoxy Arch Linux 3.0.31-1

arch linux advisories AVG-1524

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2021-20217 updated cvss 5.9

privoxy: Assertion failure triggered by a crafted CGI request

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

1.37% chance of exploitation in the next 30 days, higher than 72% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 2.0 7.8 AV:N/AC:L/Au:N/C:N/I:N/A:C

Affected products

  • n/a privoxy

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.