CVE-2020-29547
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedAn issue was discovered in Citadel through webcit-926. Meddler-in-the-middle attackers can pipeline commands after POP3 STLS, IMAP STARTTLS, or SMTP STARTTLS commands, injecting cleartext commands into an encrypted user session. This can lead to credential disclosure.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceCitadel webcit fails to properly flush pending commands during STARTTLS upgrade for POP3, IMAP, and SMTP protocols. An attacker positioned as a MitM can inject cleartext commands into the pipeline before the TLS handshake completes, causing the server to process those commands in cleartext instead of the expected encrypted session, leading to credential disclosure.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data<= 926CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- High
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- None
- Availability
- None
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Check if Citadel webcit is installedRun 'which webcit' or check for webcit in your package manager listings (dpkg -l, rpm -qa, or similar)Affected if webcit is found on the system and has not been patched to a version greater than 926
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Determine the installed webcit versionRun 'webcit --version' or query your package manager for the webcit package version (e.g., 'dpkg -l | grep webcit' or 'rpm -qa | grep webcit')Affected if The version number returned is 926 or lower
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Verify STARTTLS is enabled for affected protocolsCheck the webcit configuration files (typically in /etc/webcit or /etc/citadel) for ENABLE_POP3_STARTTLS, ENABLE_IMAP_STARTTLS, and ENABLE_SMTP_STARTTLS settings, or inspect the webcit admin interface for protocol TLS settingsAffected if STARTTLS is enabled for POP3, IMAP, or SMTP protocols in the configuration
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Test for command injection vulnerability in STARTTLS pipelineConnect to the server on the affected ports (POP3=110, IMAP=143, SMTP=25/587) and send 'STARTTLS' followed by an AUTH command or other cleartext command on the same connection without waiting for TLS completion; observe whether the server accepts and processes the cleartext commandAffected if The server accepts and responds to cleartext commands sent after STARTTLS but before the TLS handshake completes, indicating commands are not being flushed
A system is affected if it runs Citadel webcit version 926 or lower with STARTTLS enabled for POP3, IMAP, or SMTP protocols and the server accepts cleartext commands pipelined after the STARTTLS command before the TLS handshake completes.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor dataFix the STARTTLS implementation to reject or flush any commands pipelined after the STARTTLS command before initiating the TLS handshake, ensuring the encrypted session is properly established before accepting any further commands.
- Consultation2.0 h
- Implementation8.0 h
- Testing6.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,960.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2020-29547 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2020-29547 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Version or environment caveats, and links to real fixes
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