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TI-2021-13222 Aliases CVE-2021-33913GHSA-7659-433m-4fhx

libspf2 before 1.2.11 has a heap-based buffer overflow that might allow remote attackers…

Priority MEDIUM 54CWE-787Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Code execution
Confidentiality · integrity · availability
High · High · High
Fix status
No fix listed

Attack profile from CVSS 3.1 · NVD. Fix status from CNA. Impact type from CWE-787 and the CVSS impact.

Summary

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.

Why it matters now

EPSS 0.09643 95th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix No fix listed No fixed version in the sources yet

SSVC decision points

Not available: CISA has not published SSVC decision points for this record.

Affected products

VendorProductAffected versionsFixed inStatusSource
——all versions—No fix listedCNA
  • — Vendor— Affected all versions Fixed in — No fix listed CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:libspf2_project:libspf2:*:*:*:*:*:*:*:*before 1.2.11VulnerableLibspf2 Project
  • cpe:2.3:a:libspf2_project:libspf2:*:*:*:*:*:*:*:* Versions before 1.2.11 Vulnerable ·Libspf2 Project

Remediation

No fixed version listed by the sources yet.

Vendor assessments

Red Hat

Red Hat's page for this CVE →

Not affected: 1 product
  • Red Hat

Timeline

  1. 2026-10-02 Threatist record created from CVE-2021-33913
  2. 2026-10-03 Alias added: GHSA-7659-433m-4fhx

References

Exploit 1

Advisory 3

  • TI-2021-13221 libspf2 before 1.2.11 has a four-byte heap-based buffer overflow that might allow remote… CVSS 3.1CRITICAL 9.8
  • TI-2023-22486 Integer underflow in Exim libspf2 CVSS 3.1HIGH 8.8

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences