# CVE-2026-90467

## Summary

- **CVE ID:** CVE-2026-90467
- **Severity:** MEDIUM
- **CVSS Score:** 6.3 (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)
- **CWE:** CWE-88
- **Published:** Sep 12, 2026
- **Last Modified:** Sep 14, 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.

## Affected Products

- cole — aiosmtplib (0)
- cole — aiosmtplib (5.1.3)

## References

- [CNA](https://github.com/cole/aiosmtplib/commit/2e1b210714974ccc9efd0d09a8f846cb9aeaaec2)
- [CNA](https://github.com/cole/aiosmtplib/releases/tag/v5.1.3)
- [CNA](https://github.com/cole/aiosmtplib/blob/v5.1.2/src/aiosmtplib/email.py)
- [CNA](https://github.com/cole/aiosmtplib)
- [CNA](https://www.vulncheck.com/advisories/aiosmtplib-before-5.1.3-esmtp-parameter-injection-via-unvalidated-addresses)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.23%
- **EPSS Percentile:** 13.9

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-18._