Prior to 4.2.13.Final and 4.1.133.Final, Netty's chunk size parser silently overflows int, enabling request smuggling attacks. (CVE-2026-42580)
Description
Netty versions prior to 4.2.13.Final and 4.1.133.Final contain a vulnerability in the chunk size parser where an integer overflow occurs silently. This flaw enables request smuggling attacks. The issue has been fixed in versions 4.2.13.Final and 4.1.133.Final.
CVSS v3.1
Score 6.5medium
Affected software
pkg:deb/ubuntu/netty?arch=source&distro=esm-infra-legacy/trustypkg:deb/ubuntu/netty?arch=source&distro=esm-apps-legacy/xenialpkg:deb/ubuntu/netty?arch=source&distro=esm-apps/bionicpkg:deb/ubuntu/netty?arch=source&distro=esm-apps/focalpkg:deb/ubuntu/netty?arch=source&distro=esm-apps/jammypkg:deb/ubuntu/netty?arch=source&distro=esm-apps/noblepkg:deb/ubuntu/netty?arch=source&distro=questingpkg:deb/ubuntu/netty?arch=source&distro=stonkingpkg:deb/ubuntu/netty?arch=source&distro=esm-apps/resoluteRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
Netty, an asynchronous event-driven network application framework, has a vulnerability in its chunk size parser in versions before 4.2.13.Final and 4.1.133.Final. The parser silently overflows an integer value, which can be exploited to perform HTTP request smuggling attacks. This vulnerability is addressed and fixed in the specified later versions.
Potential Impact
The vulnerability allows attackers to perform request smuggling attacks, which can lead to interference with the processing of HTTP requests. According to the CVSS score of 6.5 (medium severity), the impact includes integrity and availability impacts but no confidentiality impact. There are no known exploits in the wild at this time.
Mitigation Recommendations
A fix is available in Netty versions 4.2.13.Final and 4.1.133.Final. Users should upgrade to these or later versions to remediate the vulnerability. No additional mitigation steps are indicated by the vendor advisory.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- UBUNTU-CVE-2026-42580
- Osv Schema Version
- 1.7.0
- Ecosystems
- ["Ubuntu:Pro:14.04:LTS","Ubuntu:Pro:16.04:LTS","Ubuntu:Pro:18.04:LTS","Ubuntu:Pro:20.04:LTS","Ubuntu:Pro:22.04:LTS","Ubuntu:Pro:24.04:LTS","Ubuntu:25.10","Ubuntu:26.10","Ubuntu:Pro:26.04:LTS"]
- Cvss Version
- 3.1
Threat ID: 6ad3f6812cdf04f6566671e3
Added to database: 10/17/2026, 22:28:17 UTC
Last enriched: 10/18/2026, 01:40:24 UTC
Last updated: 10/18/2026, 01:40:24 UTC
Views: 8
Community Reviews
0 reviewsCrowdsource mitigation strategies, share intel context, and vote on the most helpful responses. Sign in to add your voice and help keep defenders ahead.
Want to contribute mitigation steps or threat intel context? Sign in or create an account to join the community discussion.
Actions
Updates to AI analysis require Pro Console access. Upgrade inside Console → Billing.
Need more coverage?
Upgrade to Pro Console for AI refresh and higher limits.
For incident response and remediation, OffSeq services can help resolve threats faster.
Latest Threats
Check if your credentials are on the dark web
Instant breach scanning across billions of leaked records. Free tier available.