Vulnerability 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.
CVSS Score
CRITICAL
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Libspf2 Project | Libspf2 | < 1.2.11 |
Related Weaknesses (CWE)
References
- https://github.com/shevek/libspf2/tree/8131fe140704eaae695e76b5cd09e39bd1dd220bThird Party Advisory
- https://lists.debian.org/debian-lts-announce/2022/01/msg00015.htmlMailing ListThird Party Advisory
- https://nathanielbennett.com/blog/libspf2-cve-jan-2022-disclosureExploitThird Party Advisory
- https://security.gentoo.org/glsa/202401-22
- https://github.com/shevek/libspf2/tree/8131fe140704eaae695e76b5cd09e39bd1dd220bThird Party Advisory
- https://lists.debian.org/debian-lts-announce/2022/01/msg00015.htmlMailing ListThird Party Advisory
- https://nathanielbennett.com/blog/libspf2-cve-jan-2022-disclosureExploitThird Party Advisory
- https://security.gentoo.org/glsa/202401-22
FAQ
What is CVE-2021-33913?
CVE-2021-33913 is a vulnerability with a CVSS score of 9.8 (CRITICAL). 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 ...
How severe is CVE-2021-33913?
CVE-2021-33913 has been rated CRITICAL with a CVSS base score of 9.8/10. This is considered a critical vulnerability requiring immediate attention.
Is there a patch for CVE-2021-33913?
Check the references section above for vendor advisories and patch information. Affected products include: Libspf2 Project Libspf2.