MimeKit is a C# library which may be used for the creation and parsing of messages using the Multipurpose Internet Mail Extension (MIME), as defined by numerous IETF specifications. Prior to version 4.15.1, a CRLF injection vulnerability in MimeKit allows an attacker to embed \r\n into the SMTP envelope address local-part (when the local-part is a quoted-string). This is non-compliant with RFC 5321 and can result in SMTP command injection (e.g., injecting additional RCPT TO / DATA / RSET commands) and/or mail header injection, depending on how the application uses MailKit/MimeKit to construct and send messages. The issue becomes exploitable when the attacker can influence a MailboxAddress (MAIL FROM / RCPT TO) value that is later serialized to an SMTP session. RFC 5321 explicitly defines the SMTP mailbox local-part grammar and does not permit CR (13) or LF (10) inside Quoted-string (qtextSMTP and quoted-pairSMTP ranges exclude control characters). SMTP commands are terminated by <CRLF>, making CRLF injection in command arguments particularly dangerous. This issue has been patched in version 4.15.1.
CVSS
No CVSS.
References
Configurations
No configuration.
History
06 Mar 2026, 21:16
| Type | Values Removed | Values Added |
|---|---|---|
| New CVE |
Information
Published : 2026-03-06 21:16
Updated : 2026-03-06 21:16
NVD link : CVE-2026-30227
Mitre link : CVE-2026-30227
CVE.ORG link : CVE-2026-30227
JSON object : View
Products Affected
No product.
CWE
CWE-93
Improper Neutralization of CRLF Sequences ('CRLF Injection')