CVE-2021-33912
9.8
CRITICAL · CVSS 3.1 · EPSS 9.6% (pctl 95)
In your normal cycle
Critical by CVSS (9.8), but no sign of active exploitation.
Description
libspf2 before 1.2.11 has a four-byte 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 incorrect sprintf usage in SPF_record_expand_data in spf_expand.c. 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.
Scoring
| CVSS | 9.8 (CRITICAL, v3.1) |
|---|---|
| Vector | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| EPSS | 9.64% — more likely to be exploited than 95% of all CVEs |
| Weakness | CWE-787 |
| On CISA KEV | no |
| Public exploit | none known |
| Published | 2022-01-19 |
| Last modified | 2026-06-17 |
Affected (2)
| Vendor | Product |
|---|---|
| debian | debian linux |
| libspf2 project | libspf2 |
References
- https://github.com/shevek/libspf2/tree/8131fe140704eaae695e76b5cd09e39bd1dd220b
- https://lists.debian.org/debian-lts-announce/2022/01/msg00015.html
- https://nathanielbennett.com/blog/libspf2-cve-jan-2022-disclosure
- https://security.gentoo.org/glsa/202401-22
- https://github.com/shevek/libspf2/tree/8131fe140704eaae695e76b5cd09e39bd1dd220b
- https://lists.debian.org/debian-lts-announce/2022/01/msg00015.html
- https://nathanielbennett.com/blog/libspf2-cve-jan-2022-disclosure
- https://security.gentoo.org/glsa/202401-22
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