CVE-2026-59921

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 (\r\n). 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.

CVSS v3 5.7 MEDIUM

5.7^/10

CVSS v3 : MEDIUM

Vector :

Exploitability : 2.1 / Impact : 3.6

Attack Vector ADJACENT_NETWORK

Attack Complexity LOW

Privileges Required LOW

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact HIGH

Availability Impact NONE

Scope UNCHANGED

References

Link	Resource
https://github.com/netty/netty/security/advisories/GHSA-gcjf-9mgh-3p7g
https://github.com/netty/netty/security/advisories/GHSA-gcjf-9mgh-3p7g

Configurations

No configuration.

History

29 Jul 2026, 13:19

Type	Values Removed	Values Added
References	~~() https://github.com/netty/netty/security/advisories/GHSA-gcjf-9mgh-3p7g -~~	() https://github.com/netty/netty/security/advisories/GHSA-gcjf-9mgh-3p7g -

28 Jul 2026, 23:17

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-07-28 23:17

Updated : 2026-07-30 16:33

NVD link : CVE-2026-59921

Mitre link : CVE-2026-59921

CVE.ORG link : CVE-2026-59921

JSON object : View

Products Affected

No product.

CWE

CWE-93

Improper Neutralization of CRLF Sequences ('CRLF Injection')

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