CVE-2026-90467 MEDIUM

CVE-2026-90467: aiosmtplib before 5.1.3 ESMTP Parameter Injection via unvalidated addresses

Vendor Cole
Product aiosmtplib
Weakness CWE-88
Published September 12, 2026
Last update September 12, 2026

CVSS base score

6.3/10
Attack vector Network
Attack complexity Low
Privileges required None
User interaction None
Confidentiality —
Integrity —

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:L/SA:N

What the vulnerability does

01Description

aiosmtplib before 5.1.3 fails to properly validate email addresses supplied by callers, allowing attackers to inject ESMTP parameters into MAIL FROM and RCPT TO command lines. Attackers can craft malicious addresses containing spaces and angle brackets to append parameters like AUTH, NOTIFY, or ORCPT to envelope commands, forging authenticated identities or forcing delivery notifications to third parties.

Key dates

02Disclosure timeline

September 12, 2026 CVE published