How severe is CVE-2016-1983?

CVE-2016-1983 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-2016-1983 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (85th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2016-1983?

CVE-2016-1983 affects Privoxy. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2016-1983?

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-2016-1983 published?

CVE-2016-1983 was published on 2016-01-27 and last updated on 2026-06-17.

CVE-2016-1983

CVE-2016-1983 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-20.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 5.0
EPSS exploit prediction: 3% (85th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-20
Affected product: Privoxy
Published: 2016-01-27
Last modified: 2026-06-17

Description

The client_host function in parsers.c in Privoxy before 3.0.24 allows remote attackers to cause a denial of service (invalid read and crash) via an empty HTTP Host header.

Frequently asked questions

What is CVE-2016-1983?: The client_host function in parsers.c in Privoxy before 3.0.24 allows remote attackers to cause a denial of service (invalid read and crash) via an empty HTTP Host header.
How severe is CVE-2016-1983?: CVE-2016-1983 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-2016-1983 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (85th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2016-1983?: CVE-2016-1983 affects Privoxy. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2016-1983?: 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-2016-1983 published?: CVE-2016-1983 was published on 2016-01-27 and last updated on 2026-06-17.

References

Affected products (1)

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

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