CVE-2020-12063Public exploitNetwork attack vector

Sender spoofing via homoglyph address mismatch

Published Apr 24, 2020 · Updated Aug 4, 2024

Incorrect sender authorization in Postfix 2.10.1-7 allows remote attackers to send mail from an arbitrary-looking address via a homoglyph. The reject_unauth_sender_login_mismatch check compares only exact envelope-sender keys in smtpd_sender_login_maps, so a look-alike Unicode address misses the protected entry. The claim requires sender-login restrictions and recipients who mistake the glyphs for the configured address; Postfix's maintainer says unmatched addresses are intentionally outside that feature's scope.

CVSS severity5.3
Medium
EPSS probability0.94%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Incorrect sender authorization in Postfix 2.10.1-7 allows remote attackers to send mail from an arbitrary-looking address via a homoglyph. The reject_unauth_sender_login_mismatch check compares only exact envelope-sender keys in smtpd_sender_login_maps, so a look-alike Unicode address misses the protected entry. The claim requires sender-login restrictions and recipients who mistake the glyphs for the configured address; Postfix's maintainer says unmatched addresses are intentionally outside that feature's scope.

The record

CVE
CVE-2020-12063
Published
Apr 24, 2020
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-345, T1566
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 24, 2020CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

5.3National Vulnerability DatabaseCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
5.0National Vulnerability DatabaseAV:N/AC:L/Au:N/C:N/I:P/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-345Insufficient Verification of Data Authenticity
T1566Phishing

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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