Description
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.
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 6.0 | cyrus-imapd-2.2 | 2.2.13-19+squeeze1 | DSA-2242-1 |
| Debian 6.0 | kolab-cyrus-imapd | 2.2.13-9.1 | DSA-2258-1 |
| Debian 5.0 | cyrus-imapd-2.2 | 2.2.13-14+lenny4 | DSA-2242-1 |
| Debian 5.0 | kolab-cyrus-imapd | 2.2.13-5+lenny3 | DSA-2258-1 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 6 | cyrus-imapd +2 | 2.3.16-6.el6_1.2 | RHSA-2011:0859 |
| RHEL 5 | cyrus-imapd +3 | 2.3.7-7.el5_6.4 | RHSA-2011:0859 |
| RHEL 4 | perl-Cyrus +5 | 2.2.12-15.el4 | RHSA-2011:0859 |
Advisories 3
- RHSA-2011:0859 Red Hat Security Advisory: cyrus-imapd security update Red Hat Security Advisories (RHSA) · Jun 26, 2026
- DSA-2258-1 kolab-cyrus-imapd - implementation error Debian Security (DSA / DLA) · Mar 9, 2026
- DSA-2242-1 cyrus-imapd-2.2 - implementation error Debian Security (DSA / DLA) · Mar 9, 2026
References
- RHSA-2011:0859 vendor-advisory
- FEDORA-2011-7217 vendor-advisory
- DSA-2258 vendor-advisory
- http://www.cyrusimap.org/docs/cyrus-imapd/2.4.7/changes.php
- MDVSA-2011:100 vendor-advisory
- FEDORA-2011-7193 vendor-advisory
- 1025625 vdb-entry
- http://bugzilla.cyrusimap.org/show_bug.cgi?id=3423
- DSA-2242 vendor-advisory
- 44876 third-party-advisory
- [oss-security] 20110517 CVE Request -- Cyrus-IMAP STARTTLS issue -- [was: Re: pure-ftpd STARTTLS command injection / new CVE?] mailing-list
- VU#555316 third-party-advisory
- 44928 third-party-advisory
- 44913 third-party-advisory
- http://bugzilla.cyrusimap.org/show_bug.cgi?id=3424
- 44670 third-party-advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=705288
- cyrus-starttls-command-exec(67867) vdb-entry
- http://git.cyrusimap.org/cyrus-imapd/patch/?id=523a91a5e86c8b9a27a138f04a3e3f2d8786f162
- [oss-security] 20110517 Re: CVE Request -- Cyrus-IMAP STARTTLS issue -- [was: Re: pure-ftpd STARTTLS command injection / new CVE?] mailing-list