FedoraOperating system · Fedoraproject
CVE-2021-39272
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 · uneditedFetchmail before 6.4.22 fails to enforce STARTTLS session encryption in some circumstances, such as a certain situation with IMAP and PREAUTH.
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 confidenceFetchmail before version 6.4.22 fails to enforce STARTTLS session encryption in certain IMAP PREAUTH scenarios, potentially allowing man-in-the-middle attackers to intercept or modify email communications by downgrading the connection to cleartext.
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
FedoraOperating system
= 33= 34= 35< 6.4.22CVSS 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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Determine installed fetchmail versionRun 'fetchmail --version' or 'rpm -q fetchmail' to see the installed version numberAffected if Version is earlier than 6.4.22 (e.g., 6.4.0 through 6.4.21) or package version shows < 6.4.22
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Check if fetchmail is configured to use IMAPExamine fetchmailrc configuration file (typically ~/.fetchmailrc or /etc/fetchmailrc) and look for 'protocol imap' or 'proto imap' entriesAffected if IMAP protocol is specified in the configuration
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Identify if PREAUTH scenario is in useLook for 'preauth' option in fetchmailrc configuration; if 'preauth password' or 'preauth plain' is set, the vulnerable PREAUTH scenario is enabledAffected if Configuration contains 'preauth' directive with any authentication type
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Verify SSL/TLS enforcement for IMAPInspect fetchmailrc for 'ssl' or 'sslproto' options; check if 'nossl' is present which would disable encryptionAffected if No 'ssl' keyword is present or 'nossl' is explicitly set for IMAP connections
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Confirm operating system version on FedoraRun 'cat /etc/fedora-release' or 'rpm -q fedora-release' to determine Fedora versionAffected if Running Fedora 33, 34, or 35 with fetchmail installed
You are affected if fetchmail version is earlier than 6.4.22 AND you use IMAP protocol with PREAUTH configuration, especially without explicit SSL/TLS enforcement.
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.
dbcve · scoped6.4.22
Upgrade fetchmail to version 6.4.22 or later to enforce proper STARTTLS encryption for all IMAP connections, including PREAUTH scenarios.
Fetchmail 6.4.22 or later
- Check current fetchmail version: rpm -q fetchmail or fetchmail --version
- Update fetchmail to version 6.4.22 or later using Fedora's package manager: sudo dnf update fetchmail
- Verify the updated version: fetchmail --version
- For IMAP connections, ensure your configuration uses the 'ssl' or 'starttls' option to enforce encryption
- Test the connection to ensure STARTTLS is properly enforced
Generated from the published advisory — verify against the referenced sources before acting.
Fix this in Fedora
Scoped from the published advisory
- Consultation1.0 h
- Implementation1.0 h
- Testing1.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,200.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-39272 — 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-2021-39272 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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A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.
- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
- No spam, self-promotion, credentials, or personal data