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NVD / CVE Program· CNA apache

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…

HighCVSS 7.5 · v3.1—No exploit Fix available

Noroxi assessment

Priority: Monitor (action score 32/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 7.1% (FIRST EPSS); higher than 94.4% of all records.
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • According to CISA the attack is automatable: targets can be found by mass scanning.
  • Fixed version: org.apache.tomcat:tomcat (Maven) 8.5.8, 9.0.0.M12.

Low priority for now. Upgrade to org.apache.tomcat:tomcat (Maven) 8.5.8, 9.0.0.M12 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

Published
Aug 10, 2017
Updated
Jun 16, 2026
EPSS
7.1% · 94th percentile

Report tools

JSON

Action score

32

Monitor

Low priority for now.

CVSS
30 / 40 · 7.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
2 / 30 · 7.1%

CISA SSVC decision

Exploitation
none
Automatable
yes
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2016-6817

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
apachetomcat

Versions reported by the vendor

Affected version ranges reported by the assigning authority (apache). Independent of NVD's CPE analysis and usually ahead of it.

  • Apache Software Foundation Apache Tomcat

    • 9.0.0.M1 to 9.0.0.M11, 8.5.0 to 8.5.6affected
Affected versions · NVD (8)

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • apache tomcat8.5.0
  • apache tomcat8.5.1
  • apache tomcat8.5.2
  • apache tomcat8.5.3
  • apache tomcat8.5.4
  • apache tomcat8.5.5
  • apache tomcat8.5.6
  • apache tomcat9.0.0

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Mavenorg.apache.tomcat:tomcatfrom 8.5.0 · before 8.5.88.5.8
Mavenorg.apache.tomcat:tomcatfrom 9.0.0.M1 · before 9.0.0.M129.0.0.M12

Same product

apache: all records

Other highest-scoring records for the same primary product.

  • CVE-2025-24813Apache Tomcat: Potential RCE and/or information disclosure and/or information corruption with partial PUTKEV
    99Now
  • CVE-2016-8735Remote code execution is possible with Apache Tomcat before 6.0.48, 7.x before 7.0.73, 8.x before 8.0.39, 8.5.x before 8.5.7, and 9.x…KEV
    96Now
  • CVE-2017-12617When running Apache Tomcat versions 9.0.0.M1 to 9.0.0, 8.5.0 to 8.5.22, 8.0.0.RC1 to 8.0.46 and 7.0.0 to 7.0.81 with HTTP PUTs enabled (e.g.KEV
    92Now

Published before and after this one in the same product

  • ← EarlierCVE-2016-5018Aug 10, 2017 · In Apache Tomcat 9.0.0.M1 to 9.0.0.M9, 8.5.0 to 8.5.4, 8.0.0.RC1 to 8.0.36, 7.0.0 to 7.0.70 and 6.0.0 to 6.0.45 a malicious web application…
    39Monitor
  • ← EarlierCVE-2016-6794Aug 10, 2017 · When a SecurityManager is configured, a web application's ability to read system properties should be controlled by the SecurityManager.
    23Monitor
  • Later →CVE-2016-8745Aug 10, 2017 · A bug in the error handling of the send file code for the NIO HTTP connector in Apache Tomcat 9.0.0.M1 to 9.0.0.M13, 8.5.0 to 8.5.8…
    35Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Maven:org.apache.tomcat:tomcat8.5.8Package registry (OSV)
Maven:org.apache.tomcat:tomcat9.0.0.M12Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

Not on record for this CVE: EPSS history · patch commit or PR link · researcher credit · variant or chain candidate · public bounty program.

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-119 · Improper Restriction of Operations within the Bounds of a Memory Buffer

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

—

References

Show all references (7 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records