CVE-2021-33913
CVSS v3
9.8
CRITICAL
EPSS Score
1.4 %
exploit probability
CISA KEV
No
known exploited
Exploitation
—
SSVC status
Description
libspf2 before 1.2.11 has a heap-based buffer overflow that might allow remote attackers to execute arbitrary code (via an unauthenticated e-mail message from anywhere on the Internet) with a crafted SPF DNS record, because of SPF_record_expand_data in spf_expand.c. The amount of overflowed data depends on the relationship between the length of an entire domain name and the length of its leftmost label. The vulnerable code may be part of the supply chain of a site's e-mail infrastructure (e.g., with additional configuration, Exim can use libspf2; the Postfix web site links to unofficial patches for use of libspf2 with Postfix; older versions of spfquery relied on libspf2) but most often is not.
Technical details
- Published
- 2022-01-19
Frequently asked questions
What is CVE-2021-33913?
libspf2 before 1.2.11 has a heap-based buffer overflow that might allow remote attackers to execute arbitrary code (via an unauthenticated e-mail message from anywhere on the Internet) with a crafted SPF DNS record, because of SPF_record_expand_data in spf_expand.c. The amount of overflowed data depends on the relationship between the length of an entire domain name and the length of its leftmost label. The vulnerable code may be part of the supply chain of a site's e-mail infrastructure (e.g., with additional configuration, Exim can use libspf2; the Postfix web site links to unofficial patches for use of libspf2 with Postfix; older versions of spfquery relied on libspf2) but most often is not.
Is CVE-2021-33913 actively exploited?
Active exploitation of CVE-2021-33913 has not been confirmed. The EPSS score is 1.4%, indicating the estimated probability of exploitation in the next 30 days.
What is the CVSS score for CVE-2021-33913?
CVE-2021-33913 has a CVSS v3 base score of 9.8 (CRITICAL severity).
Is CVE-2021-33913 affecting your environment?
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