CVE-2021-20314: Fedoraproject Fedora

Critical severity, CVSS 9.8. EPSS: 2.8% chance of exploitation in the next 30 days.

Stack buffer overflow in libspf2 versions below 1.2.11 when processing certain SPF macros can lead to Denial of service and potentially code execution via malicious crafted SPF explanation messages.

Affected products

• Fedoraproject Fedora: version 33 only; version 34 only; version 35 only
• LIBSPF2 LIBSPF2: before 1.2.11 (fixed in 1.2.11)
• Red Hat Enterprise Linux: version 7.0 only

Published 2021-08-12. Last modified 2026-06-17.