MEDIUM
CVE-2021-38373
CWE-77Published: August 10, 2021· Updated: Jun 17, 2026
5.3
CVSS v3.1
Official Description
In 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 Analysis
CVE-2021-38373 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.
Exploitation requires low privileges, which limits the exposure to scenarios where an attacker has already gained initial access.
A successful exploit results in complete confidentiality breach (data exposure), with a CVSS base score of 5.3.
CVSS v3.1 Vector Breakdown
Exploitability
Attack VectorNetwork
Attack ComplexityHigh
Privileges Req.Low
User InteractionNone
ScopeUnchanged
Impact
ConfidentialityHigh
IntegrityNone
AvailabilityNone
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N
Affected Vendors & Products
kde1 product(s)
kmail
Source: NVD CPE · 1 total CPE entries
Exploit & PoC Resources
NO KNOWN EXPLOITNo public exploit confirmed at this time
Exploit-DB
Offensive Security exploit database
GitHub PoC Search
Community PoC repositories
Rapid7 / Metasploit
Metasploit module search
PacketStorm
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 (4)
→
https://bugs.kde.org/show_bug.cgi?id=423423Mailing List · Vendor Advisory
→
https://nostarttls.secvuln.infoThird Party Advisory
→
https://bugs.kde.org/show_bug.cgi?id=423423Mailing List · Vendor Advisory
→
https://nostarttls.secvuln.infoThird Party Advisory
Quick Facts
CVE IDCVE-2021-38373
CVSS Score5.3 / 10
SeverityMEDIUM
WeaknessCWE-77
CISA KEVNo
Affected1 vendor(s)
PublishedAug 10, 2021
Related CVEs (CWE-77)
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2021-38373 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.