What’s Vulnerable › Vulnerabilities

CVE-2026-59902: Netty: Memory Exhaustion in SctpMessageCompletionHandler

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-08-17 · updated 2026-09-23
• Weakness: CWE-400

Description

Netty is an asynchronous, event-driven network application framework. Prior to 4.1.137.Final and 4.2.17.Final, io.netty.handler.codec.sctp.SctpMessageCompletionHandler limits incomplete messages and fragment counts but not maxBufferedBytes, allowing unauthenticated peers to exhaust memory with large SCTP fragments. This issue is fixed in versions 4.1.137.Final and 4.2.17.Final.

Affected products

• netty: before 4.1.137; from 4.2.0 before 4.2.17 — fixed in 4.1.137, 4.2.17

How to fix

Upgrade to a fixed version: netty 4.1.137, 4.2.17. Check the vendor advisory for mitigations.

References

• https://github.com/netty/netty/commit/1b5abc6443b63726c72cdd285af2feb7ddbb8ff7
• https://github.com/netty/netty/pull/17213
• https://github.com/netty/netty/pull/17217
• https://github.com/netty/netty/releases/tag/netty-4.1.137.Final
• https://github.com/netty/netty/releases/tag/netty-4.2.17.Final
• https://github.com/netty/netty/security/advisories/GHSA-2qj4-mmr9-4v2f

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