CVE-2026-4438 (GCVE-0-2026-4438)

Vulnerability from cvelistv5 – Published: 2026-03-20 19:59 – Updated: 2026-03-23 15:06
VLAI?
Title
gethostbyaddr and gethostbyaddr_r return invalid DNS hostnames
Summary
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.
Severity ?
5.4 (Medium)
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
CWE
  • CWE-20 - Improper input validation
Assigner
References
Impacted products
Vendor Product Version
The GNU C Library glibc Affected: 2.34 , ≤ 2.43 (custom)
Create a notification for this product.
Date Public ?
2026-03-20 22:17
Credits
Antonio Maini (0rbitingZer0) - 0rbitingZer0@proton.me
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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



Detection rules are retrieved from Rulezet.