5.3

CVE-2026-5950

Unbounded resend loop in BIND 9 resolver

An unbounded resend loop vulnerability exists in the BIND 9 resolver state machine during bad-server handling, enabling a remote unauthenticated attacker to cause severe resource exhaustion by sending queries that trigger specific retry conditions.
This issue affects BIND 9 versions 9.18.36 through 9.18.48, 9.20.8 through 9.20.22, 9.21.7 through 9.21.21, 9.18.36-S1 through 9.18.48-S1, and 9.20.9-S1 through 9.20.22-S1.
Daten sind bereitgestellt durch National Vulnerability Database (NVD)
Isc ≫ Bind SwEdition- Version >= 9.18.36 < 9.18.49
Isc ≫ Bind SwEdition- Version >= 9.20.8 < 9.20.23
Isc ≫ Bind SwEdition- Version >= 9.21.7 < 9.21.21
Zu dieser CVE wurde keine Warnung gefunden.
EPSS Metriken
Typ Quelle Score Percentile
EPSS FIRST.org 0.55% 0.417
CVSS Metriken
Quelle Base Score Exploit Score Impact Score Vector String
security-officer@isc.org 5.3 3.9 1.4
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
CWE-606 Unchecked Input for Loop Condition

The product does not properly check inputs that are used for loop conditions, potentially leading to a denial of service or other consequences because of excessive looping.

https://downloads.isc.org/isc/bind9/9.18.49
Patch
https://downloads.isc.org/isc/bind9/9.20.23
Patch
https://downloads.isc.org/isc/bind9/9.21.22
Patch
https://kb.isc.org/docs/cve-2026-5950
Vendor Advisory