CVE-2026-90467
MEDIUMDescription
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.
How to fix
TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works
Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.
CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:L/A:N
Exploit Intelligence
Low risk: more likely to be exploited than 14% of all known CVEs.
References
Related Vulnerabilities
Other CWE-88 vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2016-10033 | Critical | 9.8 | 100% | KEV | Fix |
| CVE-2022-36804 | High | 8.8 | 99% | KEV | Fix |
| CVE-2007-0882 | High | 10.0 | 98% | - | - |
| CVE-2026-24061 | Critical | 9.8 | 98% | KEV | Fix |
| CVE-2018-17456 | Critical | 9.8 | 97% | - | Fix |
| CVE-2018-19518 | High | 7.5 | 95% | - | Fix |
Common questions
How do I fix CVE-2026-90467?
Upgrade aiosmtplib on debian unstable to 5.1.3-1 or later.
Is CVE-2026-90467 being actively exploited?
Not that we know of. CVE-2026-90467 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.23% is the estimated probability that it will be exploited in the next 30 days. That is higher than 14% of all scored CVEs.
How severe is CVE-2026-90467?
CVE-2026-90467 has a CVSS v3 base score of 4.0, rated medium. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
What does CVE-2026-90467 affect?
Published advisories record a fix for aiosmtplib (Debian). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.
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Markdown
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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-09-14.