<!--This ticket is confidential.--> <!--############################# Do not remove the lines above #############################--> # CVE Reservation Request <!--There's help in the Eclipse Foundation Project Handbook https://www.eclipse.org/projects/handbook/#vulnerability-cve Note that this issue is configured (see the quick actions at the bottom) to be created as confidential. Note that a vulnerability does not need to actually be resolved before it is reported and that these reports can be revised as needed (reopen the issue to request changes). If you do not know how to fill certain fields, mark that in the comment and we will help you. You can delete the comments (or not).--> The Eclipse Foundation is a [Common Vulnerabilities and Exposures](https://cve.mitre.org/) (CVE) Numbering Authority. Creating this ticket initiates **reservation** of a CVE ID for the documented vulnerability. The reserved CVE ID will be posted in a comment below, and kept **confidential** until explicit publication request. > [!note] > > To request CVE _publication_, please open a [CVE publication](https://gitlab.eclipse.org/security/cve-assignment/-/issues/new?issuable_template=CVE%20Publication%20Request&issue%5Bconfidential%5D=true) ticket. Please fill in the fields below to draft the CVE record. --- <!--Required. Specify the project's name (e.g., "Eclipse Dash") and Eclipse Foundation ID, e.g., "technology.dash".--> ## CVE record information **Project name:** Eclipse Vert.x **Project id:** rt.vertx **Versions affected:** \[4.0.0, 4.5.34\] or \[5.0.0,5.0.12\] or \[5.1.0,5.1.9\] or \[5.2.0, 5.2.0\] **Common Vulnerability Scoring System:** CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N **Summary:** 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. **Links:** https://github.com/vert-x3/vertx-mail-client/security/advisories/GHSA-rm5c-2c7f-gc5g **Credits:** Mike Read.