Goal Reached Thanks to every supporter — we hit 100%!

Goal: 1000 CNY · Raised: 1336 CNY

100%
Buy Us a Coffee

CVE-2026-53533— aiosmtplib: SMTP command injection via CR/LF in sender/recipient address

Quick assessment

Affected
cole aiosmtplib
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Cole Maclean aiosmtplib是Cole Maclean个人开发者的一个异步SMTP客户端库。 Cole Maclean aiosmtplib 5.1.1之前版本存在安全漏洞，该漏洞源于SMTP.mail()、SMTP.rcpt()、SMTP.vrfy()和SMTP.expn()方法未拒绝地址中嵌入的CR或LF字节，可能导致攻击者注入额外SMTP命令，造成命令响应管道失步、SMTP实例挂起或发送任意消息。

CVSS 6.9 · Medium EPSS 0.39% · P32

Possible ATT&CK Techniques 1 AI

T1071.008

Affected Version Matrix 1

VendorProduct Version RangeStatus
cole aiosmtplib < 5.1.1 affected
Get alerts for future matching vulnerabilities Log in to subscribe

I. Basic Information for CVE-2026-53533

Vulnerability Information
Have questions about the vulnerability? See if Shenlong's analysis helps!
View Shenlong Deep Dive ↗

Although we use advanced large model technology, its output may still contain inaccurate or outdated information.Shenlong tries to ensure data accuracy, but please verify and judge based on the actual situation.

Vulnerability Title
aiosmtplib: SMTP command injection via CR/LF in sender/recipient address
Source: CVE Program / CVE List V5
Vulnerability 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.
Source: CVE Program / CVE List V5
CVSS Information
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
Source: CVE Program / CVE List V5
Vulnerability Type
在命令中使用的特殊元素转义处理不恰当(命令注入)
Source: CVE Program / CVE List V5
Vulnerability Title
Cole Maclean aiosmtplib 命令注入漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Cole Maclean aiosmtplib是Cole Maclean个人开发者的一个异步SMTP客户端库。 Cole Maclean aiosmtplib 5.1.1之前版本存在安全漏洞，该漏洞源于SMTP.mail()、SMTP.rcpt()、SMTP.vrfy()和SMTP.expn()方法未拒绝地址中嵌入的CR或LF字节，可能导致攻击者注入额外SMTP命令，造成命令响应管道失步、SMTP实例挂起或发送任意消息。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
cole aiosmtplib < 5.1.1 -

II. Public POCs for CVE-2026-53533

# POC Description Source Link Shenlong Link
AI-Generated POC Premium

No public POC found.

Login to generate AI POC

III. Intelligence Information for CVE-2026-53533

请登录查看更多情报信息。

Patches & Fixes for CVE-2026-53533 (1)

Vendor Advisories for CVE-2026-53533 (1)

Vendor Pages for CVE-2026-53533 (1)

IV. Related Vulnerabilities

Same product: aiosmtplib
Same vendor: cole
Same weakness: CWE-77

V. Comments for CVE-2026-53533

No comments yet

Leave a comment