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Postfix through 3.8.4 allows SMTP smuggling unless...

Moderate severity Unreviewed Published Dec 24, 2023 to the GitHub Advisory Database • Updated Jun 10, 2024

Package

No package listed— Suggest a package

Affected versions

Unknown

Patched versions

Unknown

Description

Postfix through 3.8.4 allows SMTP smuggling unless configured with smtpd_data_restrictions=reject_unauth_pipelining (or certain other options that exist in recent versions). Remote attackers can use a published exploitation technique to inject e-mail messages that appear to originate from the Postfix server, allowing bypass of an SPF protection mechanism. This occurs because Postfix supports . but some other popular e-mail servers do not. To prevent attack variants (by always disallowing without ), a different solution is required: the smtpd_forbid_bare_newline=yes option with a Postfix minimum version of 3.5.23, 3.6.13, 3.7.9, 3.8.4, or 3.9.

References

Published by the National Vulnerability Database Dec 24, 2023
Published to the GitHub Advisory Database Dec 24, 2023
Last updated Jun 10, 2024

Severity

Moderate

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
None
Integrity
Low
Availability
None

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:N/I:L/A:N

EPSS score

0.298%
(70th percentile)

Weaknesses

CVE ID

CVE-2023-51764

GHSA ID

GHSA-j5jm-hg4x-w8rx

Source code

No known source code

Dependabot alerts are not supported on this advisory because it does not have a package from a supported ecosystem with an affected and fixed version.

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