Raw vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:LSummary
CVE-2026-42580 is a medium-severity Integer Overflow or Wraparound (CWE-190) vulnerability in Netty Netty. Its CVSS base score is 6.5 (Medium).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 29th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
The strongest mitigations our analysis identified map to SI-10 (Information Input Validation) and SI-2 (Flaw Remediation) — see the control section below for these in your framework.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-30123
Vulnerability Data
Netty is an asynchronous, event-driven network application framework. Prior to 4.2.13.Final and 4.1.133.Final, Netty's chunk size parser silently overflows int, enabling request smuggling attacks. This vulnerability is fixed in 4.2.13.Final and 4.1.133.Final.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Integer overflow in Netty's HTTP chunked transfer parser directly enables HTTP request smuggling against public-facing servers using the library.
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
Mitigating Controls (NIST 800-53 r5) AI
Directly requires timely application of the vendor-supplied patches (4.1.133.Final / 4.2.13.Final) that correct the integer overflow in Netty's chunk-size parser.
Mandates validation of all input fields (including Transfer-Encoding chunk sizes) to reject values that would overflow or produce inconsistent HTTP framing.
Enables continuous monitoring and anomaly detection on HTTP request streams to identify smuggling attempts that exploit the parser flaw before exploitation succeeds.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Configuration management can enforce uniform HTTP parsing rules across intermediaries, directly mitigating inconsistent interpretation.
Secure SDLC practices directly require use of safe arithmetic, bounds checks, and testing that prevent integer overflows.
Network monitoring can detect smuggling attempts via anomalous HTTP traffic or logs, while eliminating the inconsistency directly aids detection of such events.
Network protections can enforce consistent HTTP proxy/firewall behavior to block smuggling, and removing the weakness helps prevent unauthorized access via request smuggling.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Security testing in development can detect integer overflows before release.
Network security controls can enforce consistent HTTP parsing and proxy behavior that mitigates request smuggling.
Secure network services include hardening proxies and gateways against inconsistent HTTP interpretation.
Secure SDLC mandates input validation and arithmetic checks that prevent integer overflows.
Application security requirements include bounds checking and safe arithmetic to avoid overflow conditions.
Secure architecture principles require defensive coding patterns that mitigate integer wraparound risks.