The same weakness affects MIME part metadata set via MailAttachment.setContentType(), setDisposition(), setDescription(), and setContentId(), which are written directly into MIME part headers without validation.
A secondary weakness in Utils.mustEncode(char) additionally allows a bare LF in a From display-name to bypass Q-encoding and reach the wire unchanged.
An unauthenticated attacker who can control any header name, header value, or attachment metadata field passed to the mail client (for example via a web form or API that feeds into MailMessage) can exploit this to redirect email copies, spoof headers, or tamper with message structure.
The impacted component is io.vertx:vertx-mail-client.
Analysis and contextual insights are available on OpenCVE Cloud.
No vendor fix or workaround currently provided.
Additional remediation guidance may be available on OpenCVE Cloud.
Tracking
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Wed, 14 Oct 2026 20:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Weaknesses | CWE-93 |
Wed, 14 Oct 2026 19:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In Eclipse Vert.x versions [4.0.0, 4.5.34] or [5.0.0,5.0.12] or [5.1.0,5.1.9] or [5.2.0, 5.2.0], the vertx-mail-client does not sanitize CR (\r) or LF (\n) characters in user-supplied email header names and values before writing them into the SMTP DATA section. A CR/LF sequence embedded in a name or value passed to MailMessage.addHeader(), MailMessage.setHeaders(), MailAttachment.addHeader(), or MailAttachment.setHeaders() is written verbatim to the wire, allowing an attacker to inject arbitrary headers (e.g. Bcc, Reply-To, Content-Type) or prepend body content to the outgoing message. The same weakness affects MIME part metadata set via MailAttachment.setContentType(), setDisposition(), setDescription(), and setContentId(), which are written directly into MIME part headers without validation. A secondary weakness in Utils.mustEncode(char) additionally allows a bare LF in a From display-name to bypass Q-encoding and reach the wire unchanged. An unauthenticated attacker who can control any header name, header value, or attachment metadata field passed to the mail client (for example via a web form or API that feeds into MailMessage) can exploit this to redirect email copies, spoof headers, or tamper with message structure. The impacted component is io.vertx:vertx-mail-client. | |
| Title | CRLF header injection in vertx-mail-client allows manipulation of outgoing SMTP messages | |
| References |
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| Metrics |
cvssV4_0
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Subscriptions
No data.
Status: PUBLISHED
Assigner: eclipse
Published:
Updated: 2026-10-14T19:49:35.803Z
Reserved: 2026-09-29T08:34:19.768Z
Link: CVE-2026-102471
No data.
Status : Received
Published: 2026-10-14T19:17:05.180
Modified: 2026-10-14T20:17:28.363
Link: CVE-2026-102471
No data.
OpenCVE Enrichment
No data.
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CWE-93
Improper Neutralization of CRLF Sequences ('CRLF Injection')