Upstream information
Description
aiosmtplib is an asynchronous SMTP client for use with asyncio. Prior to 5.1.1, SMTP.mail(), SMTP.rcpt(), SMTP.vrfy(), and SMTP.expn() send caller-supplied addresses without rejecting embedded CR or LF bytes. Data after the line break is framed as additional standalone SMTP command lines, allowing an attacker who influences an envelope sender or recipient to inject commands such as MAIL FROM, RCPT TO, RSET, DATA, or AUTH. SMTP.sendmail() and SMTP.send() without a Message object pass addresses through the affected methods, while SMTP.send_message() is not affected. Successful injection can desynchronize the command-response pipeline, hang the SMTP instance, or send an arbitrary message without requiring attacker control of the SMTP server. This issue is fixed in version 5.1.1.SUSE information
Overall state of this security issue: Resolved
This issue is currently rated as having moderate severity.
| CVSS detail | SUSE |
|---|---|
| Base Score | 6.5 |
| Vector | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N |
| Attack Vector | Network |
| Attack Complexity | Low |
| Privileges Required | None |
| User Interaction | None |
| Scope | Unchanged |
| Confidentiality Impact | Low |
| Integrity Impact | Low |
| Availability Impact | None |
| CVSSv3 Version | 3.1 |
| CVSS detail | CNA (GitHub) | SUSE |
|---|---|---|
| Base Score | 6.9 | 6.9 |
| Vector | CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:L/SC:N/SI:H/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 | CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:L/SC:N/SI:H/SA:N |
| Attack Vector | Network | Network |
| Attack Complexity | Low | Low |
| Attack Requirements | Present | Present |
| Privileges Required | None | None |
| User Interaction | None | None |
| Vulnerable System Confidentiality Impact | None | None |
| Vulnerable System Integrity Impact | Low | Low |
| Vulnerable System Availability Impact | Low | Low |
| Subsequent System Confidentiality Impact | None | None |
| Subsequent System Integrity Impact | High | High |
| Subsequent System Availability Impact | None | None |
| CVSSv4 Version | 4.0 | 4.0 |
List of released packages
| Product(s) | Fixed package version(s) | References |
|---|---|---|
| openSUSE Tumbleweed |
| Patchnames: openSUSE-Tumbleweed-2026-11035 |
SUSE Timeline for this CVE
CVE page created: Sun Jun 14 11:52:28 2026CVE page last modified: Thu Aug 20 21:11:30 2026