// For flags

CVE-2026-4438

gethostbyaddr and gethostbyaddr_r return invalid DNS hostnames

Severity Score

5.4
*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

0
*Multiple Sources

Exploited in Wild

-
*KEV

Decision

Track
*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 result in an invalid DNS hostname being returned to the caller in violation of the DNS specification.

Llamar a gethostbyaddr o gethostbyaddr_r con un nsswitch.conf configurado que especifica el backend DNS de la biblioteca en la biblioteca GNU C versión 2.34 a la versión 2.43 podría resultar en que se devuelva un nombre de host DNS no válido al llamador en violación de la especificación DNS.

*Credits: Antonio Maini (0rbitingZer0) - 0rbitingZer0@proton.me
CVSS Scores
Attack Vector
Adjacent
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
Low
Availability
None
* Common Vulnerability Scoring System
SSVC
  • Decision:Track
Exploitation
None
Automatable
No
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-20: Improper Input Validation
  • CWE-88: Improper Neutralization of Argument Delimiters in a Command ('Argument Injection')
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