Eclipse Jetty provides a web server and servlet container. In versions 11.0.0 through 11.0.15, 10.0.0 through 10.0.15, and 9.0.0 through 9.4.52, an integer overflow in MetaDataBuilder.checkSize allows for HTTP/2 HPACK header values to
exceed their size limit. MetaDataBuilder.java determines if a header name or value exceeds the size limit, and throws an exception if the limit is exceeded. However, when length is very large and huffman is true, the multiplication by 4 in line 295
will overflow, and length will become negative. (_size+length) will now be negative, and the check on line 296 will not be triggered. Furthermore, MetaDataBuilder.checkSize allows for user-entered HPACK header value sizes to be negative, potentially leading to a very large buffer allocation later on when the user-entered size is multiplied by 2. This means that if a user provides a negative length value (or, more precisely, a length value which, when multiplied by the 4/3 fudge factor, is negative), and this length value is a very large positive number when multiplied by 2, then the user can cause a very large buffer to be allocated on the server. Users of HTTP/2 can be impacted by a remote denial of service attack. The issue has been fixed in versions 11.0.16, 10.0.16, and 9.4.53. There are no known workarounds.
| Software | From | Fixed in |
|---|---|---|
org.eclipse.jetty.http2 / http2-hpack
|
10.0.0 | 10.0.16 |
org.eclipse.jetty.http2 / http2-hpack
|
11.0.0 | 11.0.16 |
org.eclipse.jetty.http3 / http3-qpack
|
10.0.0 | 10.0.16 |
org.eclipse.jetty.http3 / http3-qpack
|
11.0.0 | 11.0.16 |
org.eclipse.jetty.http2 / http2-hpack
|
9.3.0 | 9.4.53 |
| eclipse / jetty | 11.0.0 | 11.0.16 |
| eclipse / jetty | 10.0.0 | 10.0.16 |
| eclipse / jetty | 9.3.0 | 9.4.53 |
| jenkins / jenkins | - | 2.428 |
| jenkins / jenkins | - | 2.414.3 |
| debian / debian_linux | 10.0 | 10.0.x |
| debian / debian_linux | 11.0 | 11.0.x |
| debian / debian_linux | 12.0 | 12.0.x |
A security vulnerability is a weakness in software, hardware, or configuration that can be exploited to compromise confidentiality, integrity, or availability. Many vulnerabilities are tracked as CVEs (Common Vulnerabilities and Exposures), which provide a standardized identifier so teams can coordinate patching, mitigation, and risk assessment across tools and vendors.
CVSS (Common Vulnerability Scoring System) estimates technical severity, but it doesn't automatically equal business risk. Prioritize using context like internet exposure, affected asset criticality, known exploitation (proof-of-concept or in-the-wild), and whether compensating controls exist. A "Medium" CVSS on an exposed, production system can be more urgent than a "Critical" on an isolated, non-production host.
A vulnerability is the underlying weakness. An exploit is the method or code used to take advantage of it. A zero-day is a vulnerability that is unknown to the vendor or has no publicly available fix when attackers begin using it. In practice, risk increases sharply when exploitation becomes reliable or widespread.
Recurring findings usually come from incomplete Asset Discovery, inconsistent patch management, inherited images, and configuration drift. In modern environments, you also need to watch the software supply chain: dependencies, containers, build pipelines, and third-party services can reintroduce the same weakness even after you patch a single host. Unknown or unmanaged assets (often called Shadow IT) are a common reason the same issues resurface.
Use a simple, repeatable triage model: focus first on externally exposed assets, high-value systems (identity, VPN, email, production), vulnerabilities with known exploits, and issues that enable remote code execution or privilege escalation. Then enforce patch SLAs and track progress using consistent metrics so remediation is steady, not reactive.
SynScan combines attack surface monitoring and continuous security auditing to keep your inventory current, flag high-impact vulnerabilities early, and help you turn raw findings into a practical remediation plan.