CVE-2020-15953
CVSS v3
7.4
HIGH
EPSS Score
2.4 %
exploit probability, as of 2026-09-25
CISA KEV
No
known exploited
Exploitation
—
SSVC status
Description
LibEtPan through 1.9.4, as used in MailCore 2 through 0.6.3 and other products, has a STARTTLS buffering issue that affects IMAP, SMTP, and POP3. When a server sends a "begin TLS" response, the client reads additional data (e.g., from a meddler-in-the-middle attacker) and evaluates it in a TLS context, aka "response injection."
Technical details
- Published
- 2020-07-27
Frequently asked questions
What is CVE-2020-15953?
LibEtPan through 1.9.4, as used in MailCore 2 through 0.6.3 and other products, has a STARTTLS buffering issue that affects IMAP, SMTP, and POP3. When a server sends a "begin TLS" response, the client reads additional data (e.g., from a meddler-in-the-middle attacker) and evaluates it in a TLS context, aka "response injection."
Is CVE-2020-15953 actively exploited?
Active exploitation of CVE-2020-15953 has not been confirmed. Its EPSS score was 2.4% on 2026-09-25, the estimated probability of exploitation in the next 30 days.
What is the CVSS score for CVE-2020-15953?
CVE-2020-15953 has a CVSS v3 base score of 7.4 (HIGH severity).
Is CVE-2020-15953 affecting your environment?
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