CVE-2021-33912
libspf2 - security update
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.
How to fix CVE-2021-33912
To remediate CVE-2021-33912, upgrade the affected package to a fixed version below.
- —upgrade to 1.2.11-r0 or later
- —upgrade to 1.2.10-7.1~deb11u1 or later
- —upgrade to 1.2.10-7+deb9u2 or later
Is CVE-2021-33912 being exploited?
Low — EPSS is 1.3%, meaning exploitation activity has not been observed at scale.
Affected packages (3)
- from 0, < 1.2.11-r0
- from 0, < 1.2.10-7.1~deb11u1
- from 0, < 1.2.10-7+deb9u2
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | CRITICAL9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |