// For flags

CVE-2026-4437

gethostbyaddr and gethostbyaddr_r may incorrectly handle DNS response

Severity Score

7.5
*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

0
*Multiple Sources

Exploited in Wild

-
*KEV

Decision

Attend
*SSVC
Descriptions

Calling gethostbyaddr or gethostbyaddr_r with a configured nsswitch.conf that specifies the library's DNS backend in the GNU C Library version 2.34 to version 2.43 could, with a crafted response from the configured DNS server, result in a violation of the DNS specification that causes the application to treat a non-answer section of the DNS response as a valid answer.

Llamar a gethostbyaddr o gethostbyaddr_r con un nsswitch.conf configurado que especifica el backend DNS de la biblioteca en la GNU C Library versión 2.34 a la versión 2.43 podría, con una respuesta manipulada del servidor DNS configurado, resultar en una violación de la especificación DNS que hace que la aplicación trate una sección que no es de respuesta de la respuesta DNS como una respuesta válida.

*Credits: Antonio Maini (0rbitingZer0) - 0rbitingZer0@proton.me, Kevin Farrell
CVSS Scores
Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High
* Common Vulnerability Scoring System
SSVC
  • Decision:Attend
Exploitation
None
Automatable
Yes
Tech. Impact
Partial
* Organization's Worst-case Scenario
Timeline
  • 2026-03-19 CVE Reserved
  • 2026-03-20 CVE Published
  • 2026-03-23 CVE Updated
  • 2026-05-01 EPSS Updated
  • ---------- Exploited in Wild
  • ---------- KEV Due Date
  • ---------- First Exploit
CWE
  • CWE-125: Out-of-bounds Read
CAPEC
  • CAPEC-142: DNS Cache Poisoning
Affected Vendors, Products, and Versions
Vendor Product Version Other Status
Vendor Product Version Other Status <-- --> Vendor Product Version Other Status
The GNU C Library
Search vendor "The GNU C Library"
 Glibc
Search vendor "The GNU C Library" for product "Glibc"
 >= 2.34 <= 2.43
Search vendor "The GNU C Library" for product "Glibc" and version " >= 2.34 <= 2.43"
en
Affected