CVE-2026-121946

zbateson mail-mime-parser before 3.0.9 and 4.x before 4.0.6 CRLF Header Injection via Message Builders

publishedCWE-93

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.

Technical severity6.9 mediumCVSS 4.0 · CNA: VulnCheck

Published2026-11-04Source updated 2026-11-04

Collected2026-11-041 attributed source

Fixes and workarounds

Fix

The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches.

Source: CNA: VulnCheck

Fix

The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches.

Source: CNA: VulnCheck

Fix

The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches.

Source: CNA: VulnCheck

Fix

The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches.

Source: CNA: VulnCheck

Affected products and versions

Affected products, source version ranges and reporting authorities
Product	Versions	Authority
mail-mime-parser zbateson `zbateson/mail-mime-parser` composer	≥ 0.3.0; < 3.0.9 (affected, semver) ≥ 4.0.0; < 4.0.6 (affected, semver) Other versions: unaffected	CNA: VulnCheck

Version ranges are source assertions. Check the vendor advisory and your installed configuration before determining exposure.

CVSS assessments

CVSS scores, vectors and reporting authorities
Version / score	Vector	Authority
4.0 / 6.9 medium	`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N`	CNA: VulnCheck
3.1 / 7.2 high	`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N`	CNA: VulnCheck

Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

References

https://github.com/zbateson/mail-mime-parser/security/advisories/GHSA-gmgm-r6fh-fq6gCNA: VulnCheck · vendor-advisory
https://github.com/zbateson/mail-mime-parser/commit/f385b2923023a9a7b69003468e363a4661f1c85aCNA: VulnCheck · patch
https://github.com/zbateson/mail-mime-parser/commit/1fa840ef367958e991e6840b4e3ffd41aca9d147CNA: VulnCheck · patch
https://github.com/zbateson/mail-mime-parser/commit/c31c62ccc3e66a7a7da0d79954ef83807f9daa20CNA: VulnCheck · patch
https://github.com/zbateson/mail-mime-parser/commit/b032920875c6cb35bb2ddd7abfd7e98608d75bc0CNA: VulnCheck · patch
https://github.com/zbateson/mail-mime-parser/blob/4.0.5/src/Message/Helper/MultipartHelper.php#L270-L273CNA: VulnCheck · technical-description
https://www.vulncheck.com/advisories/zbateson-mail-mime-parser-before-3.0.9-and-4-x-before-4.0.6-crlf-header-injection-via-message-buildersCNA: VulnCheck · third-party-advisory

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