CVE-2021-38373
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 · uneditedIn KDE KMail 19.12.3 (aka 5.13.3), the SMTP STARTTLS option is not honored (and cleartext messages are sent) unless "Server requires authentication" is checked.
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 confidenceIn KDE KMail 19.12.3, the SMTP STARTTLS encryption option is ignored when 'Server requires authentication' is unchecked, causing emails to be transmitted in cleartext instead of being upgraded to TLS. This occurs due to incorrect conditional logic in the mail sending code that ties STARTTLS enforcement to authentication status rather than treating them as independent settings.
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= 19.12.3CVSS 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
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- None
- Availability
- None
CVSS:3.1/AV:N/AC:H/PR:L/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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Verify KMail versionCheck if KMail is installed at version 19.12.3 specifically. Use 'kmail --version' or check the package manager. Only version 19.12.3 is affected by this CVE.Affected if The installed version is exactly 19.12.3
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Locate SMTP account configurationAccess KMail account settings via Settings > Configure KMail > Accounts > Send. Identify the SMTP server configuration being used.Affected if An SMTP account is configured with custom server settings.
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Verify STARTTLS is enabledIn the SMTP server settings, check if STARTTLS encryption or TLS is selected as the security/transmission method.Affected if STARTTLS or TLS is explicitly enabled in the account settings.
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Check if authentication is disabledIn the same SMTP account settings, verify whether the 'Server requires authentication' checkbox is unchecked.Affected if The 'Server requires authentication' option is NOT checked/enabled.
A user is affected if running KMail version 19.12.3 with STARTTLS enabled but 'Server requires authentication' unchecked, as emails will be sent in cleartext despite the STARTTLS setting.
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 dataEnable 'Server requires authentication' as a workaround until the code is patched, or migrate to a mail provider that enforces TLS at the connection level. Administrators should verify that TLS is actually being used by checking server logs or network captures.
- Consultation4.0 h
- Implementation16.0 h
- Testing8.0 h
- Review / QA4.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-38373 — 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-2021-38373 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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- 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