EUVD-2026-76774
GHSA-qh75-x5jv-g7wg
Severity by source
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Network SMTP vector, no authentication needed if attacker controls user-supplied input; scope unchanged, integrity-only impact via parameter smuggling.
Primary rating from Vendor (VulnCheck).
CVSS VectorVendor: VulnCheck
Lifecycle Timeline
4DescriptionCVE.org
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.
AnalysisAI
ESMTP parameter injection in aiosmtplib before 5.1.3 allows unauthenticated network attackers to smuggle arbitrary SMTP extension parameters into MAIL FROM and RCPT TO command lines by supplying crafted email addresses containing angle brackets and spaces. Exploitation enables forging AUTH= sender identities on cooperating SMTP servers or injecting DSN parameters (NOTIFY, ORCPT) to redirect delivery status notifications to attacker-controlled addresses. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Exploitation requires that an attacker can supply or influence an email address string that is subsequently passed to aiosmtplib's mail(), rcpt(), vrfy(), expn(), or sendmail() methods without strict pre-validation. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The CVSS 4.0 score of 6.3 with vector AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:L/SA:N correctly reflects the AT:P (attack prerequisite) condition: exploitation requires that attacker-influenced email addresses are passed to the library without prior sanitization, which is common but not universal in web applications. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | Full exploit scenario with step-by-step reproduction available after sign-in. |
| Remediation | Upgrade aiosmtplib to version 5.1.3 or later, available at https://github.com/cole/aiosmtplib/releases/tag/v5.1.3. … Detailed patch versions, workarounds, and compensating controls in full report. |
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