Vulnerability Monitor

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CVE-2021-33912


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.


Security Impact Summary

This vulnerability carries a CRITICAL severity rating with a CVSS v3.1 score of 9.8, indicating it can be exploited remotely over the network with relatively low complexity without requiring user interaction and does not require pre-existing privileges . The vulnerability impacts confidentiality (data exposure), integrity (unauthorized modifications), and availability (service disruption) for affected systems. Impacting 2 products from libspf2_project, from debian organizations running these solutions should prioritize assessment and patching.

Historical Context

Reported in 2022, this vulnerability emerged during an era marked by increased sophistication in supply chain attacks, cloud infrastructure vulnerabilities, and software-as-a-service (SaaS) security challenges. Security practices during this period emphasized zero-trust architectures, container security, and API protection.


Published

2022-01-19T18:15:07.783

Last Modified

2024-11-21T06:09:45.967

Status

Modified

Source

[email protected]

Severity

CVSSv3.1: 9.8 (CRITICAL)

CVSSv2 Vector

AV:N/AC:M/Au:N/C:C/I:C/A:C

  • Access Vector: NETWORK
  • Access Complexity: MEDIUM
  • Authentication: NONE
  • Confidentiality Impact: COMPLETE
  • Integrity Impact: COMPLETE
  • Availability Impact: COMPLETE
Exploitability Score

8.6

Impact Score

10.0

Weaknesses
  • Type: Primary
    CWE-787

Affected Vendors & Products
Type Vendor Product Version/Range Vulnerable?
Application libspf2_project libspf2 < 1.2.11 Yes
Operating System debian debian_linux 9.0 Yes

References

How SecUtils Interprets This CVE

SecUtils normalizes and enriches National Vulnerability Database (NVD) records by standardizing vendor and product identifiers, aggregating vulnerability metadata from both NVD and MITRE sources, and providing structured context for security teams. For libspf2_project's affected products, we extract Common Platform Enumeration (CPE) data, Common Weakness Enumeration (CWE) classifications, CVSS severity metrics, and reference data to enable rapid vulnerability prioritization and asset correlation. This record contains no exploit code, proof-of-concept instructions, or attack methodologies—only defensive intelligence necessary for patch management, risk assessment, and security operations.