Detections
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Echo: aiosmtplib: security update to 5.1.1

medium Tenable Cloud Security Plugin ID 464143

Description

There are packages installed that are affected by a vulnerability referenced in the following CVE:

 - 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. (CVE-2026-53533)

Solution

Update the aiosmtplib library and its related packages to version 5.1.1 or later.

See Also

https://advisory.echohq.com/cve/CVE-2026-53533

Plugin Details

Severity: Medium

ID: 464143

Version: Revision 1.1

Type: Local

Published: 10/2/2026

Updated: 10/3/2026

Supported Sensors: Tenable Cloud Security, Tenable Self-Hosted Container Security

Risk Information

VPR

Risk Factor: Medium

Score: 4.9

Percentile: 58.06

CVSS v2

Risk Factor: High

Base Score: 7.5

Temporal Score: 5.5

Vector: CVSS2#AV:N/AC:L/Au:N/C:P/I:P/A:P

CVSS Score Source: CVE-2026-53533

CVSS v3

Risk Factor: Critical

Base Score: 9.8

Temporal Score: 8.5

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

CVSS v4

Risk Factor: Medium

Base Score: 6.9

Threat Score: 2.4

Threat Vector: CVSS:4.0/E:U

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

Vulnerability Information

Exploit Ease: No known exploits are available

Patch Publication Date: 7/15/2026

Vulnerability Publication Date: 7/7/2026

Reference Information

CVE: CVE-2026-53533