CVE-2026-121946

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

Assigner: VulnCheck
Reserved: 04.11.2026 Published: 04.11.2026 Updated: 04.11.2026

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.

Metrics

CVSS Vector: 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
CVSS Score: 6.9

Exploitability Metrics		Vulnerable System Impact Metrics		Subsequent System Impact Metrics
Attack Vector	Network	Confidentiality	Low	Confidentiality	Low
Attack Complexity	Low	Integrity	Low	Integrity	Low
Attack Requirements	None	Availability	None	Availability	None
Privileges Required	None
User Interaction	None

CVSS 4.0

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N
CVSS Score: 7.2

Attack Vector	Network	Scope	Changed
Attack Complexity	Low	Confidentiality Impact	Low
Privileges Required	None	Integrity Impact	Low
User Interaction	None	Availability Impact	None

CVSS 3.1

Product Status

Vendor	zbateson
Product	mail-mime-parser
Versions	Default: unaffected affected from 0.3.0 to 3.0.9 (excl.) affected from 4.0.0 to 4.0.6 (excl.)

Vendor

zbateson

Product

mail-mime-parser

Versions

Default: unaffected

affected from 0.3.0 to 3.0.9 (excl.)
affected from 4.0.0 to 4.0.6 (excl.)

Credits

AlpetGexha finder
kemrec finder
manus-pi finder

References

Problem Types