CVE-2019-0199

CVE-2019-0199 is a high-severity vulnerability in Apache Tomcat with a CVSS 3.x base score of 7.5. Its EPSS exploit-prediction score of 73% places it in the 99th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-400.

Key facts

Description

The HTTP/2 implementation in Apache Tomcat 9.0.0.M1 to 9.0.14 and 8.5.0 to 8.5.37 accepted streams with excessive numbers of SETTINGS frames and also permitted clients to keep streams open without reading/writing request/response data. By keeping streams open for requests that utilised the Servlet API's blocking I/O, clients were able to cause server-side threads to block eventually leading to thread exhaustion and a DoS.

Frequently asked questions

What is CVE-2019-0199?
The HTTP/2 implementation in Apache Tomcat 9.0.0.M1 to 9.0.14 and 8.5.0 to 8.5.37 accepted streams with excessive numbers of SETTINGS frames and also permitted clients to keep streams open without reading/writing request/response data. By keeping streams open for requests that utilised the Servlet API's blocking I/O, clients were able to cause server-side threads to block eventually leading to thread exhaustion and a DoS.
How severe is CVE-2019-0199?
CVE-2019-0199 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-2019-0199 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 73% (99th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2019-0199?
CVE-2019-0199 primarily affects Apache Tomcat. In total, 22 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2019-0199?
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-2019-0199 published?
CVE-2019-0199 was published on 2019-04-10 and last updated on 2026-06-17.

References

Affected products (22)

More vulnerabilities in Apache Tomcat

All CVEs affecting Apache Tomcat →

Other CWE-400 (Uncontrolled Resource Consumption) vulnerabilities

Browse all CWE-400 (Uncontrolled Resource Consumption) vulnerabilities →