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.
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | |||||||||
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| netty | netty | affected |
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Advisories
| Source | ID | Title |
|---|---|---|
 Github GHSA |
GHSA-gcjf-9mgh-3p7g | Netty: CRLF Injection via Multipart Filename in Netty HttpPostRequestEncoder |
Fixes
Solution
No solution given by the vendor.
Workaround
No workaround given by the vendor.
References
History
Tue, 28 Jul 2026 22:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | A flaw was found in Netty's HttpPostRequestEncoder, a widely used Java networking library component responsible for constructing multipart HTTP request bodies. The issue arises because user-supplied filenames and field names are directly embedded into Content-Disposition MIME headers without any validation or sanitization of CRLF (\r\n) characters. Since MIME headers are delimited by CRLF sequences, an attacker who controls the filename in a multipart upload can inject arbitrary MIME headers into the request body. This may lead to limited Content-Type spoofing or header manipulation against middleware or storage layers processing the request, though the practical impact is constrained by the context in which Netty is deployed. | 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. |
| Title | io.netty/netty-codec-http: Netty: CRLF Injection via Multipart Filename in Netty HttpPostRequestEncoder | Netty: CRLF Injection via Multipart Filename in Netty HttpPostRequestEncoder |
Tue, 28 Jul 2026 00:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | A flaw was found in Netty's HttpPostRequestEncoder, a widely used Java networking library component responsible for constructing multipart HTTP request bodies. The issue arises because user-supplied filenames and field names are directly embedded into Content-Disposition MIME headers without any validation or sanitization of CRLF (\r\n) characters. Since MIME headers are delimited by CRLF sequences, an attacker who controls the filename in a multipart upload can inject arbitrary MIME headers into the request body. This may lead to limited Content-Type spoofing or header manipulation against middleware or storage layers processing the request, though the practical impact is constrained by the context in which Netty is deployed. | |
| Title | io.netty/netty-codec-http: Netty: CRLF Injection via Multipart Filename in Netty HttpPostRequestEncoder | |
| Weaknesses | CWE-93 | |
| References |
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| Metrics |
threat_severity
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cvssV3_1
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Projects
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MITRE
Status: PUBLISHED
Assigner: GitHub_M
Published:
Updated: 2026-07-28T22:28:51.267Z
Reserved: 2026-07-07T18:20:06.125Z
Link: CVE-2026-59921
Vulnrichment
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NVD
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Redhat
OpenCVE Enrichment
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Weaknesses