Description
A flaw was found in Netty's HTTP/1.1 decoder. This vulnerability allows a remote attacker to bypass `Transfer-Encoding` header validation by splitting the `Transfer-Encoding` field across multiple headers, with the last field containing a non-final transfer coding like `gzip` or `deflate`. This bypass can lead to HTTP request smuggling, enabling attackers to bypass security controls, desynchronize request processing, or cause requests to be processed in an unintended context.
References10
- access.redhat.com/errata/RHSA-2026:69440
- access.redhat.com/errata/RHSA-2026:69470
- access.redhat.com/errata/RHSA-2026:83612
- access.redhat.com/errata/RHSA-2026:95759
- access.redhat.com/errata/RHSA-2026:95760
- access.redhat.com/errata/RHSA-2026:95761
- access.redhat.com/errata/RHSA-2026:95762
- access.redhat.com/errata/RHSA-2026:95887
- access.redhat.com/security/cve/CVE-2026-93573
- bugzilla.redhat.com/show_bug.cgi?id=2536964
Metrics
- CVSS 3.1
-
6.5
MEDIUM
Score source: CNA
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N - EPSS — exploit probability
- 1% percentile: 65 · as of 8 November 2026
- CWE
- CWE-444
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.