CVE-2026-93573: Netty split Transfer-Encoding fields bypass final-chunked validation and enable request smuggling
Source GCVE Database
Not known to be exploited · CVSS 6.5 Medium : update Red Hat build of Keycloak 26.4 when convenient.
Data as of 6 Nov 2026, 14:04 UTC
Thin evidence
One scorer or none| CNA (redhat) | CVSS 3.1 | 6.5 |
|---|
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:NExploitation evidence
Disclosed: evidence found.
CVE published 18 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 6 Nov 2026.
What to do
Patches and advisories
- access.redhat.com/errata/RHSA-2026:69440 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:69470 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:83612 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:95760 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:95761 (opens in a new tab)
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| Red Hat Build of Debezium 3.6netty-codec-http | Affected– | Fixed in– |
| Red Hat build of Keycloak 26.4keycloak-rhel9-container | Affected– | Fixed in– |
| Red Hat build of Keycloak 26.4keycloak-rhel9-operator-bundle-container | Affected– | Fixed in– |
| Red Hat build of Keycloak 26.4keycloak-rhel9-operator-container | Affected– | Fixed in– |
| Red Hat build of Keycloak 26.6.8netty-codec-http | Affected– | Fixed in– |
| Red Hat build of Quarkus 3.27.5.SP2netty-codec-http | Affected– | Fixed in– |
AI-suggested
According to the Red Hat advisory linked, security updates are available in Red Hat build of Quarkus 3.33.3.SP2 which includes multiple security fixes. Users should apply the official security updates provided by their vendor or distribution to remediate this vulnerability. Patch status is confirmed with an official fix available. No additional mitigation steps are specified beyond applying the update.
Description
CVE-2026-93573 is a medium severity vulnerability in Netty where splitting Transfer-Encoding fields bypasses final-chunked validation, enabling HTTP request smuggling attacks. This flaw allows an attacker to manipulate HTTP requests by exploiting improper validation of chunked transfer encoding headers. The vulnerability has a CVSS score of 6.5 and is classified under CWE-444 (Improper Resource Shutdown or Release).
References
- nvd.nist.gov/vuln/detail/CVE-2026-93573 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:69440 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:69470 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:83612 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:95760 (opens in a new tab)
- access.redhat.com/errata/RHSA-2026:95761 (opens in a new tab)
- access.redhat.com/security/cve/CVE-2026-93573 (opens in a new tab)
- bugzilla.redhat.com/show_bug.cgi?id=2536964 (opens in a new tab)