CVE-2026-102471— CRLF header injection in vertx-mail-client allows manipulation of outgoing SMTP messages
Quick assessment
Affected
Eclipse Foundation Eclipse Vert.x
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.
在 Eclipse Vert.x 的以下版本中：[4.0.0, 4.5.34]、[5.0.0, 5.0.12]、[5.1.0, 5.1.9] 或 [5.2.0, 5.2.0]，vertx-mail-client 组件在将用户提供的电子邮件标题名称和值写入 SMTP DATA 部分之前，未对回车符（CR, \r）或换行符（LF, \n）进行过滤或净化。攻击者通过在传入 、 、 或 方法的标题名称或值中嵌入 CR/LF 序列，可将其原样写入网络传输层，从而注入任意标题（例如 Bcc、Reply-To、Content-T
Possible ATT&CK Techniques 2 AI
T1572 · Protocol Tunneling T1190 · Exploit Public-Facing ApplicationAffected Version Matrix 4
| Vendor | Product | Version Range | Status |
|---|---|---|---|
| Eclipse Foundation | Eclipse Vert.x | 4.0.0≤ 4.5.34 |
affected |
5.0.0≤ 5.0.12 |
affected | ||
5.1.0≤ 5.1.9 |
affected | ||
5.2.0 |
affected |
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I. Basic Information for CVE-2026-102471
Vulnerability Information
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Vulnerability Title
CRLF header injection in vertx-mail-client allows manipulation of outgoing SMTP messages
Source: CVE Program / CVE List V5
Vulnerability 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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N
Source: CVE Program / CVE List V5
Vulnerability Type
N/A
Source: CVE Program / CVE List V5
Affected Products
| Vendor | Product | Affected Versions | CPE | Subscribe |
|---|---|---|---|---|
| Eclipse Foundation | Eclipse Vert.x | 4.0.0 ~ 4.5.34 | - |
|
II. Public POCs for CVE-2026-102471
| # | POC Description | Source Link | Shenlong Link |
|---|
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Other References for CVE-2026-102471 (2)
Same Patch Batch · Eclipse Foundation · 2026-10-14 · 8 CVEs total
| CVE-2026-103415 | 9.3 CRITICAL | TLS 1.3 客户端缓冲区溢出漏洞 |
| CVE-2026-102476 | 9.1 CRITICAL | Eclipse Vert.x SSL缓存绕过漏洞 |
| CVE-2026-106464 | 8.7 HIGH | VxWorks 库TLS空签名解析致越界 |
| CVE-2026-106465 | 8.7 HIGH | NetX Secure DTLS服务器存在绕过验证漏洞 |
| CVE-2026-102479 | 8.7 HIGH | Vert.x 5.0-5.2 HTTP请求走私漏洞 |
| CVE-2026-102460 | 8.6 HIGH | CVE-2026-102460 |
| CVE-2026-103414 | 8.4 HIGH | GUIX二进制资源加载器缓冲区溢出漏洞 |
IV. Related Vulnerabilities
V. Comments for CVE-2026-102471
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