zbateson mail-mime-parser before 3.0.9 and 4.x before 4.0.6 contains a CRLF header injection vulnerability in
Source GCVE Database
Not known to be exploited · CVSS 6.9 Medium : upgrade to 4.0.6 or 3.0.9 when convenient.
Data as of 4 Nov 2026, 16:43 UTC
Thin evidence
One scorer or none| CNA (VulnCheck) | CVSS 4.0 | 6.9 |
|---|---|---|
| CNA (VulnCheck) | CVSS 3.1 | 7.2 |
- Patch
- Available – fixed in 4.0.6, 3.0.9
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:L/SI:L/SA:NExploitation evidence
Disclosed: evidence found.
CVE published 4 Nov 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 4 Nov 2026.
What to do
Upgrade mail-mime-parser to 4.0.6 or 3.0.9.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| zbatesonmail-mime-parser | Affected
| Fixed in
|
| zbatesonmail-mime-parser | Affected
| Fixed in
|
Packagistmail-mime-parserpkg:composer/mail-mime-parserOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
If you cannot patch yet, avoid using affected versions or sanitize inputs to message-building helpers to remove CR and LF characters. Monitor vendor channels for official patches or updates addressing this vulnerability.
Description
zbateson mail-mime-parser versions before 3.0.9 and 4.x before 4.0.6 have a CRLF header injection vulnerability. This flaw occurs in message-building helpers that do not properly strip carriage return (CR) and line feed (LF) characters. An attacker can exploit this by supplying crafted MIME type, charset, encoding, micalg, or protocol values to inject additional header lines, such as a forged Bcc, into outgoing email messages.
References
- github.com/zbateson/mail-mime-parser/security/advisories/GHSA-gmgm-r6fh-fq6g (opens in a new tab)
- nvd.nist.gov/vuln/detail/CVE-2026-121946 (opens in a new tab)
- github.com/zbateson/mail-mime-parser/commit/1fa840ef367958e991e6840b4e3ffd41aca9d147 (opens in a new tab)
- github.com/zbateson/mail-mime-parser/commit/b032920875c6cb35bb2ddd7abfd7e98608d75bc0 (opens in a new tab)
- github.com/zbateson/mail-mime-parser/commit/c31c62ccc3e66a7a7da0d79954ef83807f9daa20 (opens in a new tab)
- github.com/zbateson/mail-mime-parser/commit/f385b2923023a9a7b69003468e363a4661f1c85a (opens in a new tab)
- github.com/zbateson/mail-mime-parser/blob/4.0.5/src/Message/Helper/MultipartHelper.php (opens in a new tab)
- vulncheck.com/advisories/zbateson-mail-mime-parser-before-3.0.9-and-4-x-before-4.0.6-crlf-header-injection-via-message-builders (opens in a new tab)