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Fencer Intel
medium 5.1

CVE-2011-1926 json

The STARTTLS implementation in Cyrus IMAP Server before 2.4.7 does not properly restrict I/O buffering, which allows man-in-the-middle atta…

published 2011-05-23 15 y ago modified 2026-06-16 4 mo ago also EUVD-2011-1924

cvss
5.1
version 2.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
4.0%
EPSS 4.0% chance of exploitation in 30 days, percentile 90%
public exploits
0
none known

Summary

The STARTTLS implementation in Cyrus IMAP Server before 2.4.7 does not properly restrict I/O buffering, which allows man-in-the-middle attackers to insert commands into encrypted sessions by sending a cleartext command that is processed after TLS is in place, related to a "plaintext command injection" attack, a similar issue to CVE-2011-0411.

Patch / fix

  • cyrus-imapd RHEL 4 2.2.12-15.el4
  • cyrus-imapd RHEL 5 2.3.7-7.el5_6.4
  • cyrus-imapd RHEL 6 2.3.16-6.el6_1.2
  • perl-Cyrus RHEL 4 2.2.12-15.el4
  • cyrus-imapd-nntp RHEL 4 2.2.12-15.el4
  • cyrus-imapd-perl RHEL 5 2.3.7-7.el5_6.4
  • cyrus-imapd-utils RHEL 4 2.2.12-15.el4
  • cyrus-imapd-utils RHEL 5 2.3.7-7.el5_6.4

red hat advisories RHSA-2011:0859

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-2011-1926 updated cvss 4.0

cyrus-imapd: STARTTLS plaintext command injection

  • Red Hat Enterprise Linux (v. 5.6.z server) cyrus-imapd 2.3.7-7.el5_6.4, cyrus-imapd-perl 2.3.7-7.el5_6.4, cyrus-imapd-utils 2.3.7-7.el5_6.4 Red Hat Enterprise Linux AS version 4 perl-Cyrus 2.2.12-15.el4, cyrus-imapd 2.2.12-15.el4, cyrus-imapd-nntp 2.2.12-15.el4, cyrus-imapd-utils 2.2.12-15.el4, cyrus-imapd-murder 2.2.12-15.el4 Red Hat Enterprise Linux Desktop version 4 perl-Cyrus 2.2.12-15.el4, cyrus-imapd 2.2.12-15.el4, cyrus-imapd-nntp 2.2.12-15.el4, cyrus-imapd-utils 2.2.12-15.el4, cyrus-imapd-murder 2.2.12-15.el4 Red Hat Enterprise Linux ES version 4 perl-Cyrus 2.2.12-15.el4, cyrus-imapd 2.2.12-15.el4, cyrus-imapd-nntp 2.2.12-15.el4, cyrus-imapd-utils 2.2.12-15.el4, cyrus-imapd-murder 2.2.12-15.el4 Red Hat Enterprise Linux Server (v. 6) cyrus-imapd 2.3.16-6.el6_1.2, cyrus-imapd-utils 2.3.16-6.el6_1.2 Red Hat Enterprise Linux Server Optional (v. 6) cyrus-imapd 2.3.16-6.el6_1.2, cyrus-imapd-utils 2.3.16-6.el6_1.2
    +1 more products
    Red Hat Enterprise Linux WS version 4 perl-Cyrus 2.2.12-15.el4, cyrus-imapd 2.2.12-15.el4, cyrus-imapd-nntp 2.2.12-15.el4, cyrus-imapd-utils 2.2.12-15.el4, cyrus-imapd-murder 2.2.12-15.el4
    fixed: vendor fix RHSA-2011:0859

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

4.00% chance of exploitation in the next 30 days, higher than 90% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
NVD 2.0 5.1 AV:N/AC:H/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.