// For flags

CVE-2021-33912

Ubuntu Security Notice USN-6584-2

Severity Score

9.8
*CVSS v3.1

Exploit Likelihood

1.2%
*EPSS

Affected Versions

2
*CPE

Public Exploits

1
*Multiple Sources

Exploited in Wild

-
*KEV

Decision

-
*SSVC
Descriptions

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.

libspf2 versiones anteriores a 1.2.11, presenta un desbordamiento de búfer de cuatro bytes en la región heap de la memoria que podría permitir a atacantes remotos ejecutar código arbitrario (por medio de un mensaje de correo electrónico no autenticado desde cualquier lugar de Internet) con un registro DNS SPF diseñado, debido al uso incorrecto de sprintf en el archivo SPF_record_expand_data en spf_expand.c. El código vulnerable puede ser parte de la cadena de suministro de la infraestructura de correo electrónico de un sitio (por ejemplo, con una configuración adicional, Exim puede usar libspf2; el sitio web de Postfix enlaza con parches no oficiales para el uso de libspf2 con Postfix; las versiones más antiguas de spfquery dependían de libspf2), pero lo más frecuente es que no lo sea

USN-6584-1 fixed several vulnerabilities in Ubuntu 18.04 LTS and Ubuntu 20.04 LTS. This update provides the corresponding updates for CVE-2021-33912 andCVE-2021-33913 in Ubuntu 16.04 LTS. Philipp Jeitner and Haya Shulman discovered that Libspf2 incorrectly handled certain inputs. If a user or an automated system were tricked into opening a specially crafted input file, a remote attacker could possibly use this issue to cause a denial of service or execute arbitrary code.

*Credits: N/A
CVSS Scores
Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High
Attack Vector
Network
Attack Complexity
Medium
Authentication
None
Confidentiality
Complete
Integrity
Complete
Availability
Complete
* Common Vulnerability Scoring System
SSVC
  • Decision:-
Exploitation
-
Automatable
-
Tech. Impact
-
* Organization's Worst-case Scenario
Timeline
  • 2021-06-07 CVE Reserved
  • 2022-01-19 CVE Published
  • 2024-08-04 CVE Updated
  • 2024-08-04 First Exploit
  • 2025-04-02 EPSS Updated
  • ---------- Exploited in Wild
  • ---------- KEV Due Date
CWE
  • CWE-787: Out-of-bounds Write
CAPEC
Affected Vendors, Products, and Versions (2)