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SMTP command injection in lettre

Critical severity GitHub Reviewed Published May 22, 2021 in lettre/lettre • Updated Feb 3, 2023

Package

cargo lettre (Rust)

Affected versions

>= 0.7.0, < 0.9.6

Patched versions

0.9.6

Description

Impact

Affected versions of lettre allowed SMTP command injection through an attacker's controlled message body. The module for escaping lines starting with a period wouldn't catch a period that was placed after a double CRLF sequence, allowing the attacker to end the current message and write arbitrary SMTP commands after it.

Fix

The flaw is fixed by correctly handling consecutive CRLF sequences.

References

References

@amousset amousset published to lettre/lettre May 22, 2021
Reviewed Jun 1, 2021
Published to the GitHub Advisory Database Jul 12, 2021
Published by the National Vulnerability Database Aug 8, 2021
Last updated Feb 3, 2023

Severity

Critical

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS score

0.205%
(59th percentile)

Weaknesses

CVE ID

CVE-2021-38189

GHSA ID

GHSA-qc36-q22q-cjw3

Source code

Credits

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