CVE-2016-8740

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 verdictPatch this weekExploitation is likely or a public exploit exists.
  • 15 internet-exposed hosts are running an affected version right now
  • High exploitation likelihood — EPSS 79%
CISA-KEV: Not listedEPSS: 79%CVSS: 7.5Exploit: NoneExposed: 15

A fix is available — apply it.

The mod_http2 module in the Apache HTTP Server 2.4.17 through 2.4.23, when the Protocols configuration includes h2 or h2c, does not restrict request-header length, which allows remote attackers to cause a denial of service (memory consumption) via crafted CONTINUATION frames in an HTTP/2 request.

Live · internet exposure

15 internet-exposed hosts are running an affected version of CVE-2016-8740 right now.

across 5 countries (United States, Netherlands, Canada, Germany, Thailand)top: http_server
See the live KEV-Exposure radar →Found passively from public internet-scan data — aggregate, host-redacted.

EchelonGraph is the only CVE feed that fuses live vulnerability intelligence with its own live internet-exposure radar — so you see not just that a CVE is exploited, but how much of the internet is exposed to it right now.

CVSS v3
7.5
EG Score
7.5(medium)
EPSS
99.6%
KEV
Not listed

Published

December 5, 2016

Last Modified

May 6, 2026

References (56)

Vendor Advisories for CVE-2016-8740(3)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Patch Availability(4)

Vendor / EcosystemFixed in / PatchReleasedSource
redhatjbcs-httpd24-openssl-1:1.0.2h-13.jbcs.el62017-06-07redhat
redhatjbcs-httpd24-openssl-1:1.0.2h-13.jbcs.el72017-06-07redhat
redhatpatch2017-06-07redhat
redhathttpd24-httpd-0:2.4.25-9.el72017-04-26redhat

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.

Additional Vendor Advisories

(1)

Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.

Data Freshness Timeline

(refreshed 2× in last 7d / 20× 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. 2026-07-04 06:28 UTCEPSS rescore
  2. 2026-07-01 15:02 UTCEPSS rescore
  3. 2026-06-27 03:05 UTCEPSS rescore
  4. 2026-06-25 13:47 UTCEPSS rescore
  5. 2026-06-23 21:30 UTCEPSS rescore
  6. 2026-06-23 11:58 UTCOSV refresh
  7. 2026-06-21 14:54 UTCEPSS rescore
  8. 2026-06-21 14:54 UTCEPSS rescore
  9. 2026-06-21 01:57 UTCEPSS rescore
  10. 2026-06-21 01:57 UTCEPSS rescore
  11. 2026-06-18 17:50 UTCEPSS rescore
  12. 2026-06-18 17:50 UTCEPSS rescore
  13. 2026-06-17 17:50 UTCEPSS rescore
  14. 2026-06-17 17:50 UTCEPSS rescore
  15. 2026-06-15 17:45 UTCEPSS rescore
  16. 2026-06-14 23:14 UTCEPSS rescore
  17. 2026-06-14 23:14 UTCEPSS rescore
  18. 2026-06-12 23:09 UTCEPSS rescore
  19. 2026-06-11 13:57 UTCEPSS rescore
  20. 2026-06-08 14:14 UTCEPSS rescore
  21. 2026-06-07 15:22 UTCEPSS rescore
  22. 2026-06-07 15:22 UTCEPSS rescore
  23. 2026-06-06 13:45 UTCEPSS rescore
  24. 2026-06-06 13:45 UTCEPSS rescore
  25. 2026-06-06 13:44 UTCOSV refresh
Show 24 more
  1. 2026-06-05 06:08 UTCEPSS rescore
  2. 2026-06-05 06:08 UTCEPSS rescore
  3. 2026-06-01 13:49 UTCEPSS rescore
  4. 2026-06-01 13:49 UTCEPSS rescore
  5. 2026-05-31 22:28 UTCEPSS rescore
  6. 2026-05-31 22:28 UTCEPSS rescore
  7. 2026-05-31 00:14 UTCEPSS rescore
  8. 2026-05-29 13:41 UTCEPSS rescore
  9. 2026-05-28 13:42 UTCEPSS rescore
  10. 2026-05-28 13:42 UTCEPSS rescore
  11. 2026-05-27 13:38 UTCEPSS rescore
  12. 2026-05-27 13:38 UTCEPSS rescore
  13. 2026-05-26 13:42 UTCEPSS rescore
  14. 2026-05-26 13:42 UTCEPSS rescore
  15. 2026-05-22 21:15 UTCEPSS rescore
  16. 2026-05-22 17:46 UTCEG score recompute
  17. 2026-05-22 17:46 UTCVendor advisory
  18. 2026-05-22 17:46 UTCGHSA enrichment
  19. 2026-05-20 22:37 UTCEPSS rescore
  20. 2026-05-20 22:37 UTCEPSS rescore
  21. 2026-05-20 22:37 UTCEPSS rescore
  22. 2026-05-18 21:30 UTCEPSS rescore
  23. 2026-05-18 21:30 UTCEPSS rescore
  24. 2026-05-18 21:30 UTCEPSS rescore

Publicly available exploits

(1 reference)

Working exploit code is in the public domain (1 Exploit-DB entry). Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.

  • Exploit-DBEDB-40909
    First seen Dec 12, 2016

    Apache 2.4.23 mod_http2 - Denial of Service

    Open source ↗

Frequently asked(5)

What is CVE-2016-8740?
CVE-2016-8740 is a high vulnerability published on December 5, 2016. The mod_http2 module in the Apache HTTP Server 2.4.17 through 2.4.23, when the Protocols configuration includes h2 or h2c, does not restrict request-header length, which allows remote attackers to cause a denial of service (memory consumption) via crafted CONTINUATION frames in an HTTP/2 request.
When was CVE-2016-8740 disclosed?
CVE-2016-8740 was first published in the National Vulnerability Database on December 5, 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-2016-8740 actively exploited?
CVE-2016-8740 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 99.6% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2016-8740?
CVE-2016-8740 has a CVSS v3 base score of 7.5 (NVD).
How do I remediate CVE-2016-8740?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2016-8740, 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.

Dependency Blast Radius

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