Is CVE-2016-4979 in the CISA KEV catalog?

No. CVE-2016-4979 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2016-4979?

CVE-2016-4979 has a CVSS v3 base score of 7.5 (HIGH).

What is the EPSS score for CVE-2016-4979?

CVE-2016-4979 has an EPSS score of 18.80% (97th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2016-4979?

Upgrade apache2 on debian 11 to 2.4.23-1 or later.

CVE & CISA-KEV Catalog

CVE-2016-4979

HIGHEPSS 97th pctl

7.5

CVSS v3

NVD

Description

The Apache HTTP Server 2.4.18 through 2.4.20, when mod_http2 and mod_ssl are enabled, does not properly recognize the "SSLVerifyClient require" directive for HTTP/2 request authorization, which allows remote attackers to bypass intended access restrictions by leveraging the ability to send multiple requests over a single connection and aborting a renegotiation.

CWE-284Improper Access Control

How to fix

Remediation Available

apache2Debian

Fixed in:2.4.23-1CVE-2016-4979

TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityNone

IntegrityHigh

AvailabilityNone

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

Exploit Intelligence

18.80%probability of exploitation in 30 days

97thpercentile

Very high risk: more likely to be exploited than 97% of all known CVEs.

References

Related Vulnerabilities

Other CWE-284 (Improper Access Control) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2023-27350	Critical	9.8	100%	KEV + Ransom	Fix
CVE-2019-1653	High	7.5	100%	KEV	-
CVE-2023-23752	Medium	5.3	100%	KEV	Fix
CVE-2023-38205	High	7.5	100%	KEV	-
CVE-2023-29298	High	7.5	100%	KEV	-
CVE-2024-27348	Critical	9.8	99%	KEV	Fix

Embed a live status badge for CVE-2016-4979

Markdown

[![CVE-2016-4979](https://tridentstack.com/cve/badge/CVE-2016-4979.svg)](https://tridentstack.com/cve/CVE-2016-4979)

HTML

<a href="https://tridentstack.com/cve/CVE-2016-4979"><img src="https://tridentstack.com/cve/badge/CVE-2016-4979.svg" alt="CVE-2016-4979"></a>

Find and fix vulnerabilities across your fleet

TridentStack Control continuously scans your Windows, macOS, and Linux fleet for known vulnerabilities, prioritizes them by severity and active exploitation, and patches them automatically.

See how it works Start freeThis CVE lookup is free and always will be.

This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-05-06.