CVE-2016-4979

HIGHNVD 7.57.5—
EchelonGraph scoreMEDIUM confidence

Score 7.5 from GitHub Security Advisory (severity: HIGH) published 2022-05-13. NVD baseline CVSS 7.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
Elevated
7.5
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 19%CVSS: 7.5Exploit: NoneExposed: 0

A fix is available — apply it.

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.

CVSS v3
7.5
EG Score
7.5(medium)
EG Risk
54(Track)
EG Risk 54/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity75% × 45%
Exploitation40% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS
97.0%
KEV
Not listed

Published

July 6, 2016

Last Modified

May 6, 2026

References (50)

Patch Availability(1)

Vendor / EcosystemFixed in / PatchReleasedSource
redhathttpd24-httpd-0:2.4.18-11.el72016-07-18redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

All Vendor Advisories

(1)

Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.

Data Freshness Timeline

(refreshed 11× in last 7d / 38× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-23 14:14 UTCEPSS rescore
  2. 2026-07-23 01:23 UTCEG score recompute
  3. 2026-07-22 22:02 UTCEG score recompute
  4. 2026-07-22 14:04 UTCEPSS rescore
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  20. 2026-07-12 09:07 UTCOSV refresh
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  1. 2026-07-07 13:42 UTCEPSS rescore
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  16. 2026-06-23 21:30 UTCEPSS rescore
  17. 2026-06-23 14:30 UTCOSV refresh
  18. 2026-06-22 14:23 UTCEPSS rescore
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  39. 2026-06-07 15:22 UTCEPSS rescore
  40. 2026-06-07 15:22 UTCEPSS rescore
  41. 2026-06-06 17:59 UTCOSV refresh
  42. 2026-06-06 13:45 UTCEPSS rescore
  43. 2026-06-05 22:44 UTCEPSS rescore
  44. 2026-06-05 06:08 UTCEPSS rescore
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  51. 2026-05-31 22:28 UTCEPSS rescore
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  61. 2026-05-22 21:15 UTCEPSS rescore
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  63. 2026-05-22 19:43 UTCEG score recompute
  64. 2026-05-22 19:43 UTCVendor advisory
  65. 2026-05-22 19:42 UTCGHSA enrichment
  66. 2026-05-21 22:40 UTCEPSS rescore
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Frequently asked(5)

What is CVE-2016-4979?
CVE-2016-4979 is a high vulnerability published on July 6, 2016. The Apache HTTP Server 2.4.18 through 2.4.20, when modhttp2 and modssl 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…
When was CVE-2016-4979 disclosed?
CVE-2016-4979 was first published in the National Vulnerability Database on July 6, 2016, with the most recent update on May 6, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2016-4979 actively exploited?
CVE-2016-4979 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 97.0% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2016-4979?
CVE-2016-4979 has a CVSS v3 base score of 7.5 (NVD).
How do I remediate CVE-2016-4979?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2016-4979, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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