CVE-2026-90467
aiosmtplib before 5.1.3 ESMTP Parameter Injection via unvalidated addresses
- State
- Published
- Severity
- 6.3 Medium
- Published
- Sep 12, 2026
- Updated
- Sep 14, 2026
- Reserved
- Sep 11, 2026
Description
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 6.3 Medium | 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 | VulnCheck |
| 3.1 | 4.0 Medium | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:L/A:N | VulnCheck |
Weaknesses
- CWE-88 Improper Neutralization of Argument Delimiters in a Command ('Argument Injection')
Affected Products
| Product | Versions |
|---|---|
aiosmtplibcole |
|
References
- Patch Commitpatch
- aiosmtplib v5.1.3 Release Notesrelease-notes
- Unvalidated quote_address() in v5.1.2technical-description
- https://github.com/cole/aiosmtplibproduct
- VulnCheck Advisory: aiosmtplib before 5.1.3 ESMTP Parameter Injection via unvalidated addressesthird-party-advisory
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