CVE-2026-42581
criticalNetty is an asynchronous, event-driven network application framework.
Vendor / product: Netty — netty
Netty is an asynchronous, event-driven network application framework. Prior to 4.2.13.Final and 4.1.133.Final, HttpObjectDecoder strips a conflicting Content-Length header when a request carries both Transfer-Encoding: chunked and Content-Length, but only for HTTP/1.1 messages. The guard is absent for HTTP/1.0. An attacker that sends an HTTP/1.0 request with both headers causes Netty to decode the body as chunked while leaving Content-Length intact in the forwarded HttpMessage. Any downstream proxy or handler that trusts Content-Length over Transfer-Encoding will disagree on message boundaries, enabling request smuggling. This vulnerability is fixed in 4.2.13.Final and 4.1.133.Final.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H Affected products
Weakness classification (CWE)
Source: NVD / CISA. “NVD-CWE-Other” and “NVD-CWE-noinfo” mean NVD could not assign a specific weakness.
Mitigation & advisories
References
- https://github.com/netty/netty/security/advisories/GHSA-xxqh-mfjm-7mv9 security-advisories@github.com
- https://access.redhat.com/errata/RHSA-2026:23808 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
- https://access.redhat.com/errata/RHSA-2026:24502 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
- https://access.redhat.com/errata/RHSA-2026:25123 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
- https://access.redhat.com/errata/RHSA-2026:28010 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
- https://access.redhat.com/errata/RHSA-2026:36820 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
- https://access.redhat.com/errata/RHSA-2026:37390 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
- https://access.redhat.com/errata/RHSA-2026:42644 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
- https://access.redhat.com/errata/RHSA-2026:49700 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
- https://access.redhat.com/errata/RHSA-2026:49701 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
- https://access.redhat.com/errata/RHSA-2026:53644 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
- https://access.redhat.com/errata/RHSA-2026:53645 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
- https://access.redhat.com/errata/RHSA-2026:53646 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
- https://access.redhat.com/errata/RHSA-2026:54435 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
- https://access.redhat.com/errata/RHSA-2026:65126 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
- https://access.redhat.com/errata/RHSA-2026:66488 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
- https://access.redhat.com/errata/RHSA-2026:66545 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
- https://access.redhat.com/security/cve/CVE-2026-42581 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
- https://bugzilla.redhat.com/show_bug.cgi?id=2477232 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
- https://github.com/netty/netty/security/advisories/GHSA-xxqh-mfjm-7mv9 134c704f-9b21-4f2e-91b3-4a467353bcc0
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-42581.json 0b0ca135-0b70-47e7-9f44-1890c2a1c46c