GHSA-5x3r-wrvg-rp6q · Severity: medium · Ecosystem: maven — Netty HTTP/2: Advertised MAX_CONCURRENT_STREAMS are not enforced
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.
Conclusion & alert: CVE-2026-47244 is rated Low Risk (28.2/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.29%). Mandatory action: Monitor for updates and reassess as exploit intelligence or EPSS changes.
Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.
EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).
| # | Date | Old EPSS score | New EPSS score | Delta (New - Old) |
|---|---|---|---|---|
| 1 | 2026-06-23 | 0.51% | 0.29% | -0.21% |
| 2 | 2026-06-15 | 0.04% | 0.51% | +0.47% |
| 3 | 2026-06-12 | — | 0.04% | — |
Full EPSS history (3 records total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 5.3 | 3.1 | MEDIUM |
|
3.9 | 1.4 | [email protected] |
GHSA-5x3r-wrvg-rp6q · Severity: medium · Ecosystem: maven — Netty HTTP/2: Advertised MAX_CONCURRENT_STREAMS are not enforced
| vendor | priority | summary | link |
|---|---|---|---|
debian
|
not yet assigned | CVE-2026-47244 not yet assigned priority: Debian including 1 source packages (netty), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): open 5. | https://security-tracker.debian.org/tracker/CVE-2026-47244 |
redhat
|
medium | — | https://access.redhat.com/security/cve/CVE-2026-47244 |
suse
|
medium | — | https://www.suse.com/security/cve/CVE-2026-47244/ |
ubuntu
|
medium | CVE-2026-47244 medium priority: Ubuntu including 1 source packages (netty), 8 status rows across 8 suites (bionic, focal, jammy, noble, questing, resolute, trusty, upstream): needs-triage 8. | https://ubuntu.com/security/CVE-2026-47244 |
| URL | Tags |
|---|---|
| https://github.com/netty/netty/releases/tag/netty-4.1.135.Final | Release Notes |
| https://github.com/netty/netty/releases/tag/netty-4.2.15.Final | Release Notes |
| https://github.com/netty/netty/security/advisories/GHSA-5x3r-wrvg-rp6q | Vendor Advisory |