{"cve":"CVE-2026-47244","nvd":{"published":"2026-06-12T15:16:29.217","modified":"2026-06-17T10:54:25.803","status":"Analyzed","description":"Netty is a network application framework for development of protocol servers and clients. Prior to versions 4.1.135.Final and 4.2.15.Final, DefaultHttp2Connection.DefaultEndpoint initialises maxActiveStreams/maxStreams to Integer.MAX_VALUE, and Http2Settings never inserts SETTINGS_MAX_CONCURRENT_STREAMS by default (Http2Settings.java:305-307 only clamps a user-supplied value). Unless the application explicitly calls initialSettings().maxConcurrentStreams(n), a Netty HTTP/2 server advertises no limit and enforces none locally. Each open stream allocates a DefaultStream object, PropertyMap slots, flow-controller state and IntObjectHashMap entry; with ~2^30 permissible odd stream IDs a single TCP connection can create hundreds of thousands of long-lived stream objects. This is also the precondition for CVE-2023-44487-style Rapid-Reset amplification, where the absence of a low concurrent cap multiplies backend work. Versions 4.1.135.Final and 4.2.15.Final patch the issue.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","score":5.3},"cwes":["CWE-400"],"references":["https://github.com/netty/netty/releases/tag/netty-4.1.135.Final","https://github.com/netty/netty/releases/tag/netty-4.2.15.Final","https://github.com/netty/netty/security/advisories/GHSA-5x3r-wrvg-rp6q"],"products":["netty:netty"],"source":"nvd","synced_at":"2026-10-19T22:38:48.522727527+00:00"},"epss":{"cve":"CVE-2026-47244","score":0.00384,"percentile":0.32478,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-5x3r-wrvg-rp6q","url":"https://osv.dev/vulnerability/GHSA-5x3r-wrvg-rp6q","summary":"Netty HTTP/2: Advertised MAX_CONCURRENT_STREAMS are not enforced","modified":"2026-09-10T03:50:48.488084830Z","packages":[{"ecosystem":"Maven","name":"io.netty:netty-codec-http2","purl":"pkg:maven/io.netty/netty-codec-http2","ranges":[">=4.2.0.Final <4.2.15.Final"],"fixed":["4.2.15.Final"]},{"ecosystem":"Maven","name":"io.netty:netty-codec-http2","purl":"pkg:maven/io.netty/netty-codec-http2","ranges":["<4.1.135.Final"],"fixed":["4.1.135.Final"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}