// For flags

CVE-2020-25687

dnsmasq: heap-based buffer overflow with large memcpy in sort_rrset() when DNSSEC is enabled

Severity Score

5.9
*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

0
*Multiple Sources

Exploited in Wild

-
*KEV

Decision

-
*SSVC
Descriptions

A flaw was found in dnsmasq before version 2.83. A heap-based buffer overflow was discovered in dnsmasq when DNSSEC is enabled and before it validates the received DNS entries. This flaw allows a remote attacker, who can create valid DNS replies, to cause an overflow in a heap-allocated memory. This flaw is caused by the lack of length checks in rfc1035.c:extract_name(), which could be abused to make the code execute memcpy() with a negative size in sort_rrset() and cause a crash in dnsmasq, resulting in a denial of service. The highest threat from this vulnerability is to system availability.

Se encontró un fallo en dnsmasq versiones anteriores a 2.83. Se detectó un desbordamiento del búfer en la región heap de la memoria en dnsmasq cuando DNSSEC está habilitado y antes de comprobar las entradas DNS recibidas. Este fallo permite a un atacante remoto, que puede crear respuestas DNS válidas, causar un desbordamiento en una memoria asignada a la pila. Este fallo es causado por una falta de comprobación de longitud en la función rfc1035.c:extract_name(), que podría ser abusado para hacer que el código ejecutar memcpy() con un tamaño negativo en sort_rrset() y causar un bloqueo en dnsmasq, resultando en una denegación de servicio. La mayor amenaza de esta vulnerabilidad es la disponibilidad del sistema

A flaw was found in dnsmasq. A heap-based buffer overflow was discovered in dnsmasq when DNSSEC is enabled and before it validates the received DNS entries. This flaw allows a remote attacker, who can create valid DNS replies, to cause an overflow in a heap-allocated memory. This flaw is caused by the lack of length checks in rfc1035.c:extract_name(), which could be abused to make the code execute memcpy() with a negative size in sort_rrset() and cause a crash in dnsmasq, resulting in a denial of service. The highest threat from this vulnerability is to system availability.

*Credits: N/A
CVSS Scores
Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High
Attack Vector
Network
Attack Complexity
Medium
Authentication
None
Confidentiality
None
Integrity
None
Availability
Complete
* Common Vulnerability Scoring System
SSVC
  • Decision:-
Exploitation
-
Automatable
-
Tech. Impact
-
* Organization's Worst-case Scenario
Timeline
  • 2020-09-16 CVE Reserved
  • 2021-01-19 CVE Published
  • 2024-08-04 CVE Updated
  • 2024-11-09 EPSS Updated
  • ---------- Exploited in Wild
  • ---------- KEV Due Date
  • ---------- First Exploit
CWE
  • CWE-122: Heap-based Buffer Overflow
CAPEC
Affected Vendors, Products, and Versions
Vendor Product Version Other Status
Vendor Product Version Other Status <-- --> Vendor Product Version Other Status
Thekelleys
Search vendor "Thekelleys"
Dnsmasq
Search vendor "Thekelleys" for product "Dnsmasq"
< 2.83
Search vendor "Thekelleys" for product "Dnsmasq" and version " < 2.83"
-
Affected
Fedoraproject
Search vendor "Fedoraproject"
Fedora
Search vendor "Fedoraproject" for product "Fedora"
32
Search vendor "Fedoraproject" for product "Fedora" and version "32"
-
Affected
Fedoraproject
Search vendor "Fedoraproject"
Fedora
Search vendor "Fedoraproject" for product "Fedora"
33
Search vendor "Fedoraproject" for product "Fedora" and version "33"
-
Affected
Debian
Search vendor "Debian"
Debian Linux
Search vendor "Debian" for product "Debian Linux"
9.0
Search vendor "Debian" for product "Debian Linux" and version "9.0"
-
Affected
Debian
Search vendor "Debian"
Debian Linux
Search vendor "Debian" for product "Debian Linux"
10.0
Search vendor "Debian" for product "Debian Linux" and version "10.0"
-
Affected