Answer in brief
CVE-2026-102471 records a Medium severity (CVSS 6.9) vulnerability in CRLF header injection in vertx-mail-client allows manipulation of outgoing SMTP messages. The current sources do not mark it as known exploited. The current feed maps Eclipse Foundation/Eclipse Vert.x (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 6.9. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Eclipse Foundation/Eclipse Vert.x (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Eclipse Foundation/Eclipse Vert.xgeneric | >=4.0.0 <=4.5.34 || >=5.0.0 <=5.0.12 || >=5.1.0 <=5.1.9 || 5.2.0 | Not reported |
Published upstream
Oct 14, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Oct 14, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Oct 14, 2026
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.
Quoted source text, attributed separately from HOL analysis.