PatchTheCVECVE-2020-12063: A certain Postfix 2.10.1-7 package could allow an attacker to send an email from an arbitrary-looking sender v
CVE-2020-12063 is a medium-severity flaw (CVSS 5.3) affecting postfix. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
A certain Postfix 2.10.1-7 package could allow an attacker to send an email from an arbitrary-looking sender via a homoglyph attack, as demonstrated by the similarity of \xce\xbf to the 'o' character. This is potentially relevant when the /etc/postfix/sender_login feature is used, because a spoofed outbound message that uses a configured sender address is blocked with a "Sender address rejected: not logged in" error message, but a spoofed outboun
Why this priority
- Public exploit reference
- Remotely exploitable, no login, no user action
No fix is published yet: follow the downgrade or mitigation steps.
Risk facts
| CVSS score | 5.3 (Medium) |
| Attack vector | Network (remote) |
| Attack complexity | Low |
| Privileges needed | None |
| User interaction | None |
| EPSS exploit chance | 0.9% (top 39%) |
| CISA exploited list | No |
| Published | 2020-04-24 |
| Last modified | 2026-06-17 |
Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Am I affected?
Timeline
- Published CVE record published
- Updated Record last modified
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Quick answers
How do I fix CVE-2020-12063?
postfix: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.
Is CVE-2020-12063 being exploited?
CVE-2020-12063 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.
What does CVE-2020-12063 affect?
CVE-2020-12063 affects postfix. Severity is medium (CVSS 5.3). A certain Postfix 2.10.1-7 package could allow an attacker to send an email from an arbitrary-looking sender via a homoglyph attack, as demonstrated by the similarity of \xce\xbf to the 'o' character. This is potentially relevant when the /
How urgent is CVE-2020-12063?
Priority 44/100. Public exploit reference; Remotely exploitable, no login, no user action
Software pages
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