CVE-2011-0411

CVE-2011-0411 is a medium-severity vulnerability in Postfix with a CVSS 2.0 base score of 6.8. Its EPSS exploit-prediction score of 16% places it in the 97th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-264.

Key facts

Description

The STARTTLS implementation in Postfix 2.4.x before 2.4.16, 2.5.x before 2.5.12, 2.6.x before 2.6.9, and 2.7.x before 2.7.3 does not properly restrict I/O buffering, which allows man-in-the-middle attackers to insert commands into encrypted SMTP sessions by sending a cleartext command that is processed after TLS is in place, related to a "plaintext command injection" attack.

Frequently asked questions

What is CVE-2011-0411?
The STARTTLS implementation in Postfix 2.4.x before 2.4.16, 2.5.x before 2.5.12, 2.6.x before 2.6.9, and 2.7.x before 2.7.3 does not properly restrict I/O buffering, which allows man-in-the-middle attackers to insert commands into encrypted SMTP sessions by sending a cleartext command that is processed after TLS is in place, related to a "plaintext command injection" attack.
How severe is CVE-2011-0411?
CVE-2011-0411 has a CVSS 2.0 base score of 6.8, rated medium severity.
Is CVE-2011-0411 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 16% (97th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2011-0411?
CVE-2011-0411 primarily affects Postfix. In total, 42 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2011-0411?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2011-0411 published?
CVE-2011-0411 was published on 2011-03-16 and last updated on 2026-06-16.

References

Affected products (42)

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