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Vulnerabilities

Vulnerability · CVE-2016-6817

The HTTP/2 header parser in Apache Tomcat 9.0.0.M1 to 9.0.0.M11 and 8.5.0 to 8.5.6 entered an infinite loop if a header was received that was larger than the available buffer.

Published Aug 10, 2017 · catalog updated Jun 17, 2026 · The HTTP/2 header parser

Last checked Nov 6, 2026. A connected source was read within the last 7 days.

Check if you run it

No confirmed exploitation is on record for CVE-2016-6817. EPSS is 7.19%. Act only if a listed version of The HTTP/2 header parser is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (The HTTP/2 header parser).
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.

Same product and reporting

Severity
High7.5
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
7.19%
Remediation
Advisory link
Affected products
cpe apache/tomcat

The HTTP/2 header parser in Apache Tomcat 9.0.0.M1 to 9.0.0.M11 and 8.5.0 to 8.5.6 entered an infinite loop if a header was received that was larger than the available buffer. This made a denial of service attack possible.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe apache/tomcat8.5.0
  • cpe apache/tomcat8.5.1
  • cpe apache/tomcat8.5.2
  • cpe apache/tomcat8.5.3
  • cpe apache/tomcat8.5.4
  • cpe apache/tomcat8.5.5

How to fix CVE-2016-6817

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2016-6817. EPSS is 7.19%. Act only if a listed version of The HTTP/2 header parser is installed.

Which versions are affected?

Compare what you have installed with 8.5.0, 8.5.1, 8.5.2, 8.5.3, 8.5.4, 8.5.5. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-119: Buffer Overflow; CWE-835: Infinite Loop. EPSS 7.19%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Technology hubs

Apache Tomcat security

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Aug 10, 2017 · Monitored products — critical

    Detected

    The HTTP/2 header parser in Apache Tomcat 9.0.0.M1 to 9.0.0.M11 and 8.5.0 to 8.5.6 entered an infinite loop if a header was received that was larger than the available buffer. This made a denial of service attack possible.

  2. Jun 17, 2026 · Monitored products — critical

    Updated

    The HTTP/2 header parser in Apache Tomcat 9.0.0.M1 to 9.0.0.M11 and 8.5.0 to 8.5.6 entered an infinite loop if a header was received that was larger than the available buffer. This made a denial of service attack possible.

Sources

  • CVE.orgVulnerability recordCVE-2016-6817

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2016-6817

    30-day exploitation probability 7.19%

    first.org
  • Monitored products — criticalVendor advisoryCVE-2016-6817

    The HTTP/2 header parser in Apache Tomcat 9.0.0.M1 to 9.0.0.M11 and 8.5.0 to 8.5.6 entered an infinite loop if a header was received that was larger than the available buffer. This made a denial of service attack possible.

    nvd.nist.gov

References

Freshness

Last verified in this catalog Nov 6, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • FIRST EPSSNov 6, 2026
  • CVE.orgNov 4, 2026
  • Monitored products — criticalNov 3, 2026