Vulnerability in Zbateson Mail-Mime-Parser
CVE-2026-121946
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.
Vulnerability class: CRLF Injection
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.2 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N.
EPSS exploit prediction
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Affected products
Weakness classification (CWE)
References
- github.com/zbateson/mail-mime-parser/security/advisories/GHSA-gmgm-r6fh-fq6g (vendor-advisory)
- github.com/zbateson/mail-mime-parser/commit/f385b2923023a9a7b69003468e363a4661f… (patch)
- github.com/zbateson/mail-mime-parser/commit/1fa840ef367958e991e6840b4e3ffd41aca… (patch)
- github.com/zbateson/mail-mime-parser/commit/c31c62ccc3e66a7a7da0d79954ef83807f9… (patch)
- github.com/zbateson/mail-mime-parser/commit/b032920875c6cb35bb2ddd7abfd7e98608d… (patch)
- github.com/zbateson/mail-mime-parser/blob/4.0.5/src/Message/Helper/MultipartHel… (technical-description)
- www.vulncheck.com/advisories/zbateson-mail-mime-parser-before-3.0.9-and-4-x-bef… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-121946?
- CVE-2026-121946 is a high-severity vulnerability in Zbateson Mail-Mime-Parser, classified under CRLF Injection. CVSS score: 7.2/10. Published 2026-11-04.
- How severe is CVE-2026-121946?
- High severity. CVSS v3 base score is 7.2 out of 10.