CVE Vulnerabilities

CVE-2026-59921

Improper Neutralization of CRLF Sequences ('CRLF Injection')

Published: Jul 28, 2026 | Modified: Aug 07, 2026
CVSS 3.x
6.5
MEDIUM
Source:
NVD
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N
CVSS 2.x
RedHat/V2
RedHat/V3
5.7 MODERATE
CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N
Ubuntu
MEDIUM
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Netty is an asynchronous, event-driven network application framework. Prior to versions 4.1.136.Final and 4.2.16.Final, HttpPostRequestEncoder constructs multipart HTTP request bodies by directly concatenating user-supplied filenames and field names into Content-Disposition MIME headers without validating or sanitizing CRLF characters (rn). Since MIME headers are delimited by CRLF, an attacker who controls the filename can inject arbitrary MIME headers into the multipart body part. The root cause is that neither the encoder nor the FileUpload implementations setFilename() methods, which only check for null, neutralize CRLF characters before the filename is embedded into the header. This issue has been fixed in versions 4.1.136.Final and 4.2.16.Final.

Weakness

The product uses CRLF (carriage return line feeds) as a special element, e.g. to separate lines or records, but it does not neutralize or incorrectly neutralizes CRLF sequences from inputs.

Affected Software

NameVendorStart VersionEnd Version
NettyNetty*4.1.136 (excluding)
NettyNetty4.2.0 (including)4.2.16 (excluding)
Red Hat build of Quarkus 3.27.4.SP3RedHatnetty-codec-http*
Red Hat build of Quarkus 3.33.2.SP3RedHatnetty-codec-http*

Potential Mitigations

References