MEDIUM
CVE-2011-1926
CWE-264Published: May 23, 2011· Updated: Jun 16, 2026
5.1
CVSS v3.1
Official 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.
Technical Analysis
CVE-2011-1926 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.
Exploitation requires some privileges, which limits the exposure to scenarios where an attacker has already gained initial access.
CVSS v3.1 Vector Breakdown
Exploitability
Attack VectorNetwork
Attack ComplexityHigh
Privileges Req.
User Interaction
Scope
Impact
ConfidentialityP
IntegrityP
AvailabilityP
AV:N/AC:H/Au:N/C:P/I:P/A:P
Affected Vendors & Products
cmu1 product(s)
cyrus imap server
Source: NVD CPE · 35 total CPE entries
Exploit & PoC Resources
NO KNOWN EXPLOITNo public exploit confirmed at this time
Exploit-DB
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GitHub PoC Search
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Rapid7 / Metasploit
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Security advisories & exploits
NVD Detail
Official NIST entry
MITRE CVE
CVE Program entry
External links open in a new tab. Always verify in a controlled environment before use.
Official Patches & Advisories
All References (40)
→
http://www.kb.cert.org/vuls/id/555316US Government Resource
Quick Facts
CVE IDCVE-2011-1926
CVSS Score5.1 / 10
SeverityMEDIUM
WeaknessCWE-264
CISA KEVNo
Affected1 vendor(s)
PublishedMay 23, 2011
Related CVEs (CWE-264)
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2011-1926 in threat intel feeds
- →Review IDS/IPS signatures for exploitation attempts
Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWATCH.COM. CVE data is provided under the NVD usage policy.