CVE-2016-6817
CVE-2016-6817 is a high-severity vulnerability in Apache Tomcat with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-119.
Key facts
- Severity: High (CVSS 3.x base score 7.5)
- CVSS v2: 5.0
- EPSS exploit prediction: 7% (94th percentile)
- Actively exploited: Not listed in CISA KEV
- Weakness: CWE-119
- Affected product: Apache Tomcat
- Published:
- Last modified:
Description
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.
Frequently asked questions
- What is 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. This made a denial of service attack possible.
- How severe is CVE-2016-6817?
- CVE-2016-6817 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
- Is CVE-2016-6817 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 7% (94th percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2016-6817?
- CVE-2016-6817 primarily affects Apache Tomcat. In total, 18 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
- How do I fix CVE-2016-6817?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
- When was CVE-2016-6817 published?
- CVE-2016-6817 was published on 2017-08-10 and last updated on 2026-06-17.
References
- http://www.securityfocus.com/bid/94462
- http://www.securitytracker.com/id/1037330
- https://lists.apache.org/thread.html/343558d982879bf88ec20dbf707f8c11255f8e219e81d45c4f8d0551%40%3Cdev.tomcat.apache.org%3E
- https://lists.apache.org/thread.html/6af47120905aa7d8fe12f42e8ff2284fb338ba141d3b77b8c7cb61b3%40%3Cdev.tomcat.apache.org%3E
- https://lists.apache.org/thread.html/88855876c33f2f9c532ffb75bfee570ccf0b17ffa77493745af9a17a%40%3Cdev.tomcat.apache.org%3E
- https://lists.apache.org/thread.html/a9f24571460af003071475b75f18cad81ebcc36fa7c876965a75e32a%40%3Cannounce.tomcat.apache.org%3E
- https://lists.apache.org/thread.html/b5e3f51d28cd5d9b1809f56594f2cf63dcd6a90429e16ea9f83bbedc%40%3Cdev.tomcat.apache.org%3E
- https://security.netapp.com/advisory/ntap-20180607-0001/
Affected products (18)
- cpe:2.3:a:apache:tomcat:8.5.0:*:*:*:*:*:*:*
- cpe:2.3:a:apache:tomcat:8.5.1:*:*:*:*:*:*:*
- cpe:2.3:a:apache:tomcat:8.5.2:*:*:*:*:*:*:*
- cpe:2.3:a:apache:tomcat:8.5.3:*:*:*:*:*:*:*
- cpe:2.3:a:apache:tomcat:8.5.4:*:*:*:*:*:*:*
- cpe:2.3:a:apache:tomcat:8.5.5:*:*:*:*:*:*:*
- cpe:2.3:a:apache:tomcat:8.5.6:*:*:*:*:*:*:*
- cpe:2.3:a:apache:tomcat:9.0.0:milestone1:*:*:*:*:*:*
- cpe:2.3:a:apache:tomcat:9.0.0:milestone10:*:*:*:*:*:*
- cpe:2.3:a:apache:tomcat:9.0.0:milestone11:*:*:*:*:*:*
- cpe:2.3:a:apache:tomcat:9.0.0:milestone2:*:*:*:*:*:*
- cpe:2.3:a:apache:tomcat:9.0.0:milestone3:*:*:*:*:*:*
- cpe:2.3:a:apache:tomcat:9.0.0:milestone4:*:*:*:*:*:*
- cpe:2.3:a:apache:tomcat:9.0.0:milestone5:*:*:*:*:*:*
- cpe:2.3:a:apache:tomcat:9.0.0:milestone6:*:*:*:*:*:*
- cpe:2.3:a:apache:tomcat:9.0.0:milestone7:*:*:*:*:*:*
- cpe:2.3:a:apache:tomcat:9.0.0:milestone8:*:*:*:*:*:*
- cpe:2.3:a:apache:tomcat:9.0.0:milestone9:*:*:*:*:*:*
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