Buffer overflow in Libspf2 Project
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.
Vulnerability class: Buffer Overflow
EPSS: 0.096 (95.2th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
Affected products
- Libspf2_project Libspf2
- N/a — versions n/a
Weakness classification (CWE)
Public proof-of-concept exploits
References
- cve@mitre.org (Third Party Advisory)
- cve@mitre.org (Exploit, Third Party Advisory)
- cve@mitre.org (mailing-list, Mailing List, Third Party Advisory)
- cve@mitre.org (vendor-advisory)
Frequently asked questions
- What is CVE-2021-33913?
- CVE-2021-33913 is a critical-severity vulnerability in Libspf2 Project, classified under Out-of-bounds Write. CVSS score: 9.8/10. Published 2022-01-19.
- How severe is CVE-2021-33913?
- Critical severity. CVSS v3 base score is 9.8 out of 10.
- Is CVE-2021-33913 known to be exploited?
- 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.