Mail is an internet library for Ruby designed to handle email generation, parsing, and sending. Prior to 2.9.1, Mail::Utilities.q_value_decode and Mail::Utilities.b_value_decode used a single String#match and an overly greedy charset capture to decode only the first RFC 2047 encoded-word and mishandle surrounding or subsequent text. A crafted malformed encoded-word in an address display name or local part could cross ? delimiters and make decoded From, To, or Reply-To header values differ from the raw values inspected by a human reviewer or downstream parser, enabling apparent sender or recipient spoofing, phishing, or authorization-check bypass. This issue is fixed in version 2.9.1.
Metrics
Affected Vendors & Products
References
History
Wed, 02 Sep 2026 17:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| First Time appeared |
Mikel
Mikel mail |
|
| Vendors & Products |
Mikel
Mikel mail |
Wed, 02 Sep 2026 16:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Metrics |
ssvc
|
Tue, 01 Sep 2026 22:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | Mail is an internet library for Ruby designed to handle email generation, parsing, and sending. Prior to 2.9.1, Mail::Utilities.q_value_decode and Mail::Utilities.b_value_decode used a single String#match and an overly greedy charset capture to decode only the first RFC 2047 encoded-word and mishandle surrounding or subsequent text. A crafted malformed encoded-word in an address display name or local part could cross ? delimiters and make decoded From, To, or Reply-To header values differ from the raw values inspected by a human reviewer or downstream parser, enabling apparent sender or recipient spoofing, phishing, or authorization-check bypass. This issue is fixed in version 2.9.1. | |
| Title | Mail: Email address spoofing via malformed RFC 2047 encoded-words | |
| Weaknesses | CWE-436 | |
| References |
| |
| Metrics |
cvssV3_1
|
Status: PUBLISHED
Assigner: GitHub_M
Published: 2026-09-01T20:09:20.820Z
Updated: 2026-09-02T15:44:56.368Z
Reserved: 2026-07-16T19:35:57.767Z
Link: CVE-2026-63435
Updated: 2026-09-02T15:44:51.475Z
Status : Deferred
Published: 2026-09-01T21:18:35.287
Modified: 2026-09-09T21:09:13.080
Link: CVE-2026-63435
No data.