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Fencer Intel
medium 6.8

CVE-2011-0411 json

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 proper…

published 2011-03-16 15 y ago modified 2026-06-16 4 mo ago also EUVD-2011-0437

cvss
6.8
version 2.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
16.3%
EPSS 16.3% chance of exploitation in 30 days, percentile 96%
public exploits
0
none known

Summary

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.

Patch / fix

  • postfix Debian 14, Debian 13, Debian 12 2.8.0-1

debian advisories DEBIAN-CVE-2011-0411

  • postfix RHEL 6 2:2.6.6-2.1.el6_0
  • postfix-perl-scripts RHEL 6 2:2.6.6-2.1.el6_0
  • postfix RHEL 4 2:2.2.10-1.4.el4
  • postfix RHEL 5 2:2.3.3-2.2.el5_6
  • postfix-pflogsumm RHEL 4 2:2.2.10-1.4.el4
  • postfix-pflogsumm RHEL 5 2:2.3.3-2.2.el5_6

red hat advisories RHSA-2011:0423RHSA-2011:0422

  • pure-ftpd openSUSE Tumbleweed 1.0.43-1.3

opensuse advisories openSUSE-SU-2024:10318-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2011-0411 updated cvss 4.0

postfix: SMTP commands injection during plaintext to TLS session switch

  • Red Hat Enterprise Linux (v. 5.6.z server) postfix 2.3.3-2.2.el5_6, postfix-pflogsumm 2.3.3-2.2.el5_6 Red Hat Enterprise Linux AS version 4 postfix 2.2.10-1.4.el4, postfix-pflogsumm 2.2.10-1.4.el4
    fixed: vendor fix RHSA-2011:0422
  • Red Hat Enterprise Linux Desktop (v. 6) postfix 2.6.6-2.1.el6_0, postfix-perl-scripts 2.6.6-2.1.el6_0 Red Hat Enterprise Linux Desktop Optional (v. 6) postfix 2.6.6-2.1.el6_0, postfix-perl-scripts 2.6.6-2.1.el6_0
    fixed: vendor fix RHSA-2011:0423
  • Red Hat Enterprise Linux Desktop version 4 postfix 2.2.10-1.4.el4, postfix-pflogsumm 2.2.10-1.4.el4 Red Hat Enterprise Linux ES version 4 postfix 2.2.10-1.4.el4, postfix-pflogsumm 2.2.10-1.4.el4
    fixed: vendor fix RHSA-2011:0422
  • Red Hat Enterprise Linux HPC Node (v. 6) postfix 2.6.6-2.1.el6_0, postfix-perl-scripts 2.6.6-2.1.el6_0 Red Hat Enterprise Linux HPC Node Optional (v. 6) postfix 2.6.6-2.1.el6_0, postfix-perl-scripts 2.6.6-2.1.el6_0 Red Hat Enterprise Linux Server (v. 6) postfix 2.6.6-2.1.el6_0, postfix-perl-scripts 2.6.6-2.1.el6_0 Red Hat Enterprise Linux Server Optional (v. 6) postfix 2.6.6-2.1.el6_0, postfix-perl-scripts 2.6.6-2.1.el6_0 Red Hat Enterprise Linux Workstation (v. 6) postfix 2.6.6-2.1.el6_0, postfix-perl-scripts 2.6.6-2.1.el6_0 Red Hat Enterprise Linux Workstation Optional (v. 6) postfix 2.6.6-2.1.el6_0, postfix-perl-scripts 2.6.6-2.1.el6_0
    fixed: vendor fix RHSA-2011:0423
  • Red Hat Enterprise Linux WS version 4 postfix 2.2.10-1.4.el4, postfix-pflogsumm 2.2.10-1.4.el4
    fixed: vendor fix RHSA-2011:0422

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

16.33% chance of exploitation in the next 30 days, higher than 96% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • postfix.org http://www.postfix.org/CVE-2011-0411.html referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 2.0 6.8 AV:N/AC:M/Au:N/C:P/I:P/A:P

Classification

Weakness
  • CWE-264 Permissions, Privileges, and Access Controls

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.