CVE-2021-20209
A memory leak vulnerability was found in Privoxy before 3.0.29 in the show-status CGI handler...
A memory leak vulnerability was found in Privoxy before 3.0.29 in the show-status CGI handler when no action files are configured.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Exploit likelihood
What each source reports
NVD Score used
A memory leak vulnerability was found in Privoxy before 3.0.29 in the show-status CGI handler when no action files are configured.
- Record
CVE-2021-20209- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - CVSS 2.0
- 5.0 Medium
AV:N/AC:L/Au:N/C:N/I:N/A:P - Weakness
- CWE-401
- Updated
- 2026-11-02
CVE List No score
A memory leak vulnerability was found in Privoxy before 3.0.29 in the show-status CGI handler when no action files are configured.
- Record
CVE-2021-20209- Weakness
- CWE-401
- Updated
- 2026-11-02
EUVDEUVD-2021-7652 No score
A memory leak vulnerability was found in Privoxy before 3.0.29 in the show-status CGI handler when no action files are configured.
- Record
EUVD-2021-7652- Updated
- 2026-11-03
GitHub AdvisoriesGHSA-qf5g-m559-vx7x No score
A memory leak vulnerability was found in Privoxy before 3.0.29 in the show-status CGI handler...
A memory leak vulnerability was found in Privoxy before 3.0.29 in the show-status CGI handler when no action files are configured.
- Record
GHSA-qf5g-m559-vx7x- Weakness
- CWE-401
- Updated
- 2026-11-02
OSV
A memory leak vulnerability was found in Privoxy before 3.0.29 in the show-status CGI handler when no action files are configured.
- Record
CVE-2021-20209- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
OSVDEBIAN-CVE-2021-20209
A memory leak vulnerability was found in Privoxy before 3.0.29 in the show-status CGI handler when no action files are configured.
- Record
DEBIAN-CVE-2021-20209- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
OSVUBUNTU-CVE-2021-20209
A memory leak vulnerability was found in Privoxy before 3.0.29 in the show-status CGI handler when no action files are configured.
- Record
UBUNTU-CVE-2021-20209- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
OSVUSN-4886-1 No score
privoxy vulnerabilities
It was discovered that Privoxy incorrectly handled CGI requests. An attacker could possibly use this issue to cause a denial of service or obtain sensitive information. (CVE-2020-35502, CVE-2021-20209, CVE-2021-20210, CVE-2021-20213, CVE-2021-20215, CVE-2021-20216, CVE-2021-20217, CVE-2021-20272, CVE-2021-20273, CVE-2021-20275)
It was discovered that Privoxy incorrectly handled certain regular expressions. An attacker could possibly use this issue to cause a denial of service or obtain sensitive information. (CVE-2021-20212, CVE-2021-20276)
It was discovered that Privoxy incorrectly handled client tags. An attacker could possibly use this issue to cause Privoxy to consume resources, resulting in a denial of service. This issue only affected Ubuntu 18.04 LTS, Ubuntu 20.04 LTS and Ubuntu 20.10. (CVE-2021-20211)
It was discovered that Privoxy incorrectly handled client tags. An attacker could possibly use this issue to cause Privoxy to consume resources, resulting in a denial of service. This issue only affected Ubuntu 20.04 LTS and Ubuntu 20.10. (CVE-2021-20214)
- Record
USN-4886-1- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
privoxyDebian:12 |
before 3.0.29-1 | 3.0.29-1 |
privoxyDebian:13 |
before 3.0.29-1 | 3.0.29-1 |
privoxyDebian:14 |
before 3.0.29-1 | 3.0.29-1 |
privoxyDebian:9 From an advisory covering 9 CVEs |
before 3.0.26-3+deb9u1, plus listed versions 3.0.26-3 |
3.0.26-3+deb9u1 |
privoxyUbuntu:Pro:14.04:LTS |
before 3.0.21-7+deb8u1ubuntu0.1~esm1, plus listed versions 3.0.21-13.0.21-23.0.21-7+deb8u1build0.14.04.1 |
3.0.21-7+deb8u1ubuntu0.1~esm1 |
privoxyUbuntu:16.04:LTS |
before 3.0.24-1ubuntu0.1, plus listed versions 3.0.23-33.0.23-43.0.23-53.0.24-1 |
3.0.24-1ubuntu0.1 |
privoxyUbuntu:18.04:LTS |
before 3.0.26-5ubuntu0.1, plus listed versions 3.0.26-33.0.26-43.0.26-5 |
3.0.26-5ubuntu0.1 |
privoxyUbuntu:20.04:LTS |
before 3.0.28-2ubuntu0.1, plus listed versions 3.0.28-2 |
3.0.28-2ubuntu0.1 |
privoxyUbuntu:Pro:14.04:LTS From an advisory covering 14 CVEs |
before 3.0.21-7+deb8u1ubuntu0.1~esm1, plus listed versions 3.0.21-13.0.21-23.0.21-7+deb8u1build0.14.04.1 |
3.0.21-7+deb8u1ubuntu0.1~esm1 |
privoxyUbuntu:16.04:LTS From an advisory covering 14 CVEs |
before 3.0.24-1ubuntu0.1, plus listed versions 3.0.23-33.0.23-43.0.23-53.0.24-1 |
3.0.24-1ubuntu0.1 |
privoxyUbuntu:18.04:LTS From an advisory covering 14 CVEs |
before 3.0.26-5ubuntu0.1, plus listed versions 3.0.26-33.0.26-43.0.26-5 |
3.0.26-5ubuntu0.1 |
privoxyUbuntu:20.04:LTS From an advisory covering 14 CVEs |
before 3.0.28-2ubuntu0.1, plus listed versions 3.0.28-2 |
3.0.28-2ubuntu0.1 |
History
| Recorded | Changed | Sources |
|---|---|---|
| affected, facts | ||
| aliases | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2021-20209 is a high vulnerability (CVSS 7.5) in Privoxy, published February 3, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.90%, the 79th percentile. Fixed in privoxy 3.0.29-1.
References
privoxy.org/3.0.29/user-manual/whatsnew.html
bugzilla.redhat.com/show_bug.cgi?id=1928726
security.gentoo.org/glsa/202107-16
nvd.nist.gov/vuln/detail/CVE-2021-20209
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github.com/advisories/GHSA-qf5g-m559-vx7x
security-tracker.debian.org/tracker/CVE-2021-20209
ubuntu.com/security/CVE-2021-20209
openwall.com/lists/oss-security/2021/02/03/3
cve.org/CVERecord?id=CVE-2021-20209