CVE-2021-38502 - CVE House
Back to Database
Status published Medium CVE-2021-38502

Thunderbird ignored the configuration to require STARTTLS security for an...

Vulnerability Description

Thunderbird ignored the configuration to require STARTTLS security for an SMTP connection. A MITM could perform a downgrade attack to intercept transmitted messages, or could take control of the authenticated session to execute SMTP commands chosen by the MITM. If an unprotected authentication method was configured, the MITM could obtain the authentication credentials, too. This vulnerability affects Thunderbird < 91.2.

Impact Analysis

Refer to official advisory for detailed impact metrics.

Remediation

Ensure systems are updated to the latest vendor-supplied patch levels.

THREAT MONITOR

Am I Vulnerable?

Launch our assessment wizard to check if your infrastructure is exposed to • CVE-2021-38502

Credits & Attribution

No credits recorded in the NVD database.

References

More from Mozilla

View All →
CVE-2025-9187
Memory safety bugs fixed in Firefox 142 and Thunderbird 142
Unknown 0
CVE-2025-9186
Spoofing issue in the Address Bar component of Firefox Focus for Android
Unknown 0
CVE-2025-9185
Memory safety bugs fixed in Firefox ESR 115.27, Firefox ESR 128.14, Thunderbird ESR 128.14, Firefox ESR 140.2, Thunderbird ESR 140.2, Firefox 142 and Thunderbird 142
Unknown 0
CVE-2025-9184
Memory safety bugs fixed in Firefox ESR 140.2, Thunderbird ESR 140.2, Firefox 142 and Thunderbird 142
Unknown 0
CVE-2025-9183
Spoofing issue in the Address Bar component
Unknown 0

Affected Vendor

Affected Software

Thunderbird
Vulnerable Versions:
unspecified

Timeline

Official Publish: November 3rd, 2021
Last Modified: August 4th, 2024
Added to House: July 21st, 2026

CVSS Vectors

V3: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

Weaknesses (CWE)

No CWE data available

MITRE ATT&CK TTPs

No associated TTPs found for this vulnerability.