How severe is CVE-2021-20213?

CVE-2021-20213 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2021-20213 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (72nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-20213?

CVE-2021-20213 affects Privoxy. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-20213?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2021-20213 published?

CVE-2021-20213 was published on 2021-03-25 and last updated on 2026-06-17.

CVE-2021-20213

CVE-2021-20213 is a high-severity vulnerability in Privoxy with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-476.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 4.3
EPSS exploit prediction: 2% (72nd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-476
Affected product: Privoxy
Published: 2021-03-25
Last modified: 2026-06-17

Description

A flaw was found in Privoxy in versions before 3.0.29. Dereference of a NULL-pointer that could result in a crash if accept-intercepted-requests was enabled, Privoxy failed to get the request destination from the Host header and a memory allocation failed.

Frequently asked questions

What is CVE-2021-20213?: A flaw was found in Privoxy in versions before 3.0.29. Dereference of a NULL-pointer that could result in a crash if accept-intercepted-requests was enabled, Privoxy failed to get the request destination from the Host header and a memory allocation failed.
How severe is CVE-2021-20213?: CVE-2021-20213 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2021-20213 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (72nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-20213?: CVE-2021-20213 affects Privoxy. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-20213?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2021-20213 published?: CVE-2021-20213 was published on 2021-03-25 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:privoxy:privoxy:*:*:*:*:*:*:*:*

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