CVE-2026-75595

CVE Enrichment

CVSS: 9.1 CRITICAL
EPSS: 0.28%
EPSS Percentile: 19.11%
CISA KEV: Not listed

Description

Netty is an asynchronous, event-driven network application framework. Prior to 4.1.137.Fina and 4.2.17.Final, io.netty.handler.ssl.SslClientHelloHandler#decode checks the wrong offset before reading the four-byte TLS handshake header, so a ClientHello whose handshake header spans records can cause an IndexOutOfBoundsException and invoke select(ctx, null). This selects the default SslContext instead of the SNI-specific context. In deployments where per-SNI clientAuth=REQUIRE is the sole mutual TLS gate, the default SslContext uses clientAuth=NONE or clientAuth=OPTIONAL, and no application-layer certificate verification exists, an unauthenticated remote attacker can bypass the protected route's mutual TLS requirement. This issue is fixed in versions 4.1.137.Final and 4.2.17.Final.

Technical Details

CVSS Version: 4.0
CNA / NVD Source: [email protected]
Published: 20-Aug-2026 04:17
Last Modified: 23-Sep-2026 02:33
EPSS Date: 2026-10-22
CWE: CWE-754

CVSS Vector


            CVSS:4.0                            AV:N /
                            AC:L /
                            AT:P /
                            PR:N /
                            UI:N /
                            VC:H /
                            VI:H /
                            VA:N /
                            SC:N /
                            SI:N /
                            SA:N /
                            E:X /
                            CR:X /
                            IR:X /
                            AR:X /
                            MAV:X /
                            MAC:X /
                            MAT:X /
                            MPR:X /
                            MUI:X /
                            MVC:X /
                            MVI:X /
                            MVA:X /
                            MSC:X /
                            MSI:X /
                            MSA:X /
                            S:X /
                            AU:X /
                            R:X /
                            V:X /
                            RE:X /
                            U:X

Affected Products / Versions

netty / netty
Version / affected range: * · before (exclusive) 4.1.137
cpe:2.3:a:netty:netty:*:*:*:*:*:*:*:*
netty / netty
Version / affected range: * · from (inclusive) 4.2.0 · before (exclusive) 4.2.17
cpe:2.3:a:netty:netty:*:*:*:*:*:*:*:*

References

Last enrichment sync: 23-Oct-2026 17:28
Sources: NVD · FIRST EPSS · CISA KEV
Latest successful provider update; providers refresh independently.

Reported Context (1)

CVE-2026-75595 – a Netty issue listed for Confluence, Jira Software, and Jira Service Management. Atlassian October Bulletin Covers 75 Third-Party CVEs Across Its Products

CVE (7)

Vendors (1)

Products (8)

Note: Related entities, including threat actors, malware, CVEs, MITRE ATT&CK techniques, vendors, products, tools, countries, and industries, are shown when they appear in the same reporting. Their presence does not necessarily mean they were targeted, compromised, vulnerable, responsible for the activity, or directly involved in the incident.