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.
Published: n/a
Score: 5.7 Medium
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

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Tracking

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Advisories
Source ID Title
Github GHSA Github GHSA GHSA-gcjf-9mgh-3p7g Netty: CRLF Injection via Multipart Filename in Netty HttpPostRequestEncoder
History

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
Metrics threat_severity

None

 cvssV3_1

{'score': 5.7, 'vector': 'CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N'}

threat_severity

Moderate

Subscriptions

No data.

cve-icon MITRE

No data.

cve-icon Vulnrichment

No data.

cve-icon NVD

No data.

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-07-09T00:00:00Z

Links: CVE-2026-59921 - Bugzilla

cve-icon OpenCVE Enrichment

No data.

Weaknesses
  • CWE-93

    Improper Neutralization of CRLF Sequences ('CRLF Injection')