Vulnerability · Published Nov 4, 2026 · Assigned by VulnCheck
CVE-2026-121946zbateson mail-mime-parser before 3.0.9 and 4.x before 4.0.6 CRLF Header Injection via Message Builders
High 7.2
In plain English
A high-severity security flaw in mail-mime-parser from zbateson. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 26% of all known vulnerabilities).
Severity (CVSS 3.1)7.2High
Exploit odds (30 days)0.3%top 74.3% of all CVEs
Exploited in the wildNo reportsCISA SSVC: poc
Attack toolingNoneno public tooling known
Official description
zbateson mail-mime-parser before 3.0.9 and 4.x before 4.0.6 contains a CRLF header injection vulnerability in message-building helpers that fail to strip CR and LF characters. Attackers supplying crafted MIME type, charset, encoding, micalg, or protocol values can inject extra header lines such as a forged Bcc into outgoing messages.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| zbateson | mail-mime-parser | 0.3.0 – before 3.0.94.0.0 – before 4.0.6 |
Weakness: CWE-93 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N
References
- GitHub Security Advisory (GHSA-gmgm-r6fh-fq6g) vendor-advisory
- https://github.com/zbateson/mail-mime-parser/commit/f385b2923023a9a7b69003468e363a4661f1c85a patch
- https://github.com/zbateson/mail-mime-parser/commit/1fa840ef367958e991e6840b4e3ffd41aca9d147 patch
- https://github.com/zbateson/mail-mime-parser/commit/c31c62ccc3e66a7a7da0d79954ef83807f9daa20 patch
- https://github.com/zbateson/mail-mime-parser/commit/b032920875c6cb35bb2ddd7abfd7e98608d75bc0 patch
- https://github.com/zbateson/mail-mime-parser/blob/4.0.5/src/Message/Helper/MultipartHelper.php#L270-L273 technical-description
- VulnCheck Advisory: zbateson mail-mime-parser before 3.0.9 and 4.x before 4.0.6 CRLF Header Injection via Message Builders third-party-advisory