The STARTTLS implementation in Cyrus IMAP Server before 2.4.7 does not properly restrict I/O buffering, which allows man-in-the-middle attac
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.
- Published
- May 23, 2011
- Updated
- Jun 16, 2026
- EPSS
- 4.0% · 90th percentile
- CWE
- CWE-264
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Report tools
Action score
21
Monitor
Low priority for now.
- CVSS
- 20 / 40 · 5.1 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 1 / 30 · 4.0%
Affected systems
| Vendor | Product | CPE |
|---|---|---|
| cmu | cyrus imap server | cpe:2.3:a:cmu:cyrus_imap_server |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- cmu cyrus imap serverup to 2.4.6 inclusive
- cmu cyrus imap server2.0.17
- cmu cyrus imap server2.1.16
- cmu cyrus imap server2.1.17
- cmu cyrus imap server2.1.18
- cmu cyrus imap server2.2.10
- cmu cyrus imap server2.2.11
- cmu cyrus imap server2.2.12
- cmu cyrus imap server2.2.13
- cmu cyrus imap server2.2.13p1
- cmu cyrus imap server2.2.8
- cmu cyrus imap server2.2.9
- cmu cyrus imap server2.3.0
- cmu cyrus imap server2.3.1
- cmu cyrus imap server2.3.10
- cmu cyrus imap server2.3.11
- cmu cyrus imap server2.3.12
- cmu cyrus imap server2.3.13
- cmu cyrus imap server2.3.14
- cmu cyrus imap server2.3.15
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Debian:5.0 | cyrus-imapd-2.2 | before 2.2.13-14+lenny4 | 2.2.13-14+lenny4 |
| Debian:5.0 | kolab-cyrus-imapd | before 2.2.13-5+lenny3 | 2.2.13-5+lenny3 |
| Debian:6.0 | cyrus-imapd-2.2 | before 2.2.13-19+squeeze1 | 2.2.13-19+squeeze1 |
| Debian:6.0 | kolab-cyrus-imapd | before 2.2.13-9.1 | 2.2.13-9.1 |
| Red Hat:enterprise_linux:4::as | cyrus-imapd | before 0:2.2.12-15.el4 | 0:2.2.12-15.el4 |
| Red Hat:enterprise_linux:4::as | cyrus-imapd-debuginfo | before 0:2.2.12-15.el4 | 0:2.2.12-15.el4 |
| Red Hat:enterprise_linux:4::as | cyrus-imapd-devel | before 0:2.2.12-15.el4 | 0:2.2.12-15.el4 |
| Red Hat:enterprise_linux:4::as | cyrus-imapd-murder | before 0:2.2.12-15.el4 | 0:2.2.12-15.el4 |
| Red Hat:enterprise_linux:4::as | cyrus-imapd-nntp | before 0:2.2.12-15.el4 | 0:2.2.12-15.el4 |
| Red Hat:enterprise_linux:4::as | cyrus-imapd-utils | before 0:2.2.12-15.el4 | 0:2.2.12-15.el4 |
| Red Hat:enterprise_linux:4::as | perl-Cyrus | before 0:2.2.12-15.el4 | 0:2.2.12-15.el4 |
| Red Hat:enterprise_linux:5::server | cyrus-imapd | before 0:2.3.7-7.el5_6.4 | 0:2.3.7-7.el5_6.4 |
| Red Hat:enterprise_linux:5::server | cyrus-imapd-debuginfo | before 0:2.3.7-7.el5_6.4 | 0:2.3.7-7.el5_6.4 |
| Red Hat:enterprise_linux:5::server | cyrus-imapd-devel | before 0:2.3.7-7.el5_6.4 | 0:2.3.7-7.el5_6.4 |
| Red Hat:enterprise_linux:5::server | cyrus-imapd-perl | before 0:2.3.7-7.el5_6.4 | 0:2.3.7-7.el5_6.4 |
| Red Hat:enterprise_linux:5::server | cyrus-imapd-utils | before 0:2.3.7-7.el5_6.4 | 0:2.3.7-7.el5_6.4 |
| Red Hat:enterprise_linux:6::server | cyrus-imapd | before 0:2.3.16-6.el6_1.2 | 0:2.3.16-6.el6_1.2 |
| Red Hat:enterprise_linux:6::server | cyrus-imapd-debuginfo | before 0:2.3.16-6.el6_1.2 | 0:2.3.16-6.el6_1.2 |
| Red Hat:enterprise_linux:6::server | cyrus-imapd-devel | before 0:2.3.16-6.el6_1.2 | 0:2.3.16-6.el6_1.2 |
| Red Hat:enterprise_linux:6::server | cyrus-imapd-utils | before 0:2.3.16-6.el6_1.2 | 0:2.3.16-6.el6_1.2 |
Same product
cmu: all recordsOther highest-scoring records for the same primary product.
- CVE-2011-3208Stack-based buffer overflow in the split_wildmats function in nntpd.c in nntpd in Cyrus IMAP Server before 2.3.17 and 2.4.x before 2.4.11 al32Monitor
- CVE-2011-3481The index_get_ids function in index.c in imapd in Cyrus IMAP Server before 2.4.11, when server-side threading is enabled, allows remote atta18Monitor
- CVE-2009-2632Buffer overflow in the SIEVE script component (sieve/script.c), as used in cyrus-imapd in Cyrus IMAP Server 2.2.13 and 2.3.14, and Dovecot 117Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| debian:cyrus-imapd-2.2 | 2.2.13-14+lenny4 · Debian:5.0 | Package registry (OSV) |
| debian:kolab-cyrus-imapd | 2.2.13-9.1 · Debian:6.0 | Package registry (OSV) |
| red hat:cyrus-imapd | 0:2.2.12-15.el4 · Red Hat:enterprise_linux:4::as | Package registry (OSV) |
| red hat:cyrus-imapd-debuginfo | 0:2.2.12-15.el4 · Red Hat:enterprise_linux:4::as | Package registry (OSV) |
| red hat:cyrus-imapd-devel | 0:2.2.12-15.el4 · Red Hat:enterprise_linux:4::as | Package registry (OSV) |
| red hat:cyrus-imapd-murder | 0:2.2.12-15.el4 · Red Hat:enterprise_linux:4::as | Package registry (OSV) |
| red hat:cyrus-imapd-nntp | 0:2.2.12-15.el4 · Red Hat:enterprise_linux:4::as | Package registry (OSV) |
| red hat:cyrus-imapd-perl | 0:2.3.7-7.el5_6.4 · Red Hat:enterprise_linux:5::server | Package registry (OSV) |
| red hat:cyrus-imapd-utils | 0:2.2.12-15.el4 · Red Hat:enterprise_linux:4::as | Package registry (OSV) |
| red hat:perl-Cyrus | 0:2.2.12-15.el4 · Red Hat:enterprise_linux:4::as | Package registry (OSV) |
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- Special conditions such as timing or configuration are required.
If successful
- Confidentiality
- P · data can be read
- Integrity
- P · data or configuration can be modified
- Availability
- P · the service can be disrupted
- Attack complexity
- High
- Confidentiality impact
- P
- Integrity impact
- P
- Availability impact
- P
Weakness class (CWE)
CWE-264 · Permissions, Privileges, and Access ControlsCVSS vector
AV:N/AC:H/Au:N/C:P/I:P/A:P
nvd-primary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
MITRE has no CAPEC/ATT&CK mapping for this CWE.
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpChange log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
- bugzilla.cyrusimap.org/show_bug.cgi?id=3423
- bugzilla.cyrusimap.org/show_bug.cgi?id=3424
- git.cyrusimap.org/cyrus-imapd/patch/?id=523a91a5e86c8b9a27a138f04a3e3f2d8786f162
- lists.fedoraproject.org/pipermail/package-announce/2011-June/061374.html
- lists.fedoraproject.org/pipermail/package-announce/2011-June/061415.html
- openwall.com/lists/oss-security/2011/05/17/15
- openwall.com/lists/oss-security/2011/05/17/2
- secunia.com/advisories/44670
- secunia.com/advisories/44876
- secunia.com/advisories/44913
- secunia.com/advisories/44928
- www.cyrusimap.org/docs/cyrus-imapd/2.4.7/changes.php
- www.debian.org/security/2011/dsa-2242
- www.debian.org/security/2011/dsa-2258
- www.kb.cert.org/vuls/id/555316
- www.mandriva.com/security/advisories?name=MDVSA-2011:100
- www.redhat.com/support/errata/RHSA-2011-0859.html
- www.securitytracker.com/id?1025625
- bugzilla.redhat.com/show_bug.cgi?id=705288
- exchange.xforce.ibmcloud.com/vulnerabilities/67867
Vendor advisories and official records. Exploit/PoC links are deliberately left out.