CVE-2026-5950

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.

CVSS v3 5.3 MEDIUM

5.3^/10

CVSS v3 : MEDIUM

Vector :

Exploitability : 3.9 / Impact : 1.4

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact LOW

Scope UNCHANGED

References

Link	Resource
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

Configurations

Configuration 1 (hide)

OR	cpe:2.3:a:isc:bind:::::-:::*
	cpe:2.3:a:isc:bind:::::-:::*
	cpe:2.3:a:isc:bind:::::-:::*

History

21 May 2026, 15:24

Type	Values Removed	Values Added
References	~~() https://downloads.isc.org/isc/bind9/9.18.49 -~~	() https://downloads.isc.org/isc/bind9/9.18.49 - Patch
References	~~() https://downloads.isc.org/isc/bind9/9.20.23 -~~	() https://downloads.isc.org/isc/bind9/9.20.23 - Patch
References	~~() https://downloads.isc.org/isc/bind9/9.21.22 -~~	() https://downloads.isc.org/isc/bind9/9.21.22 - Patch
References	~~() https://kb.isc.org/docs/cve-2026-5950 -~~	() https://kb.isc.org/docs/cve-2026-5950 - Vendor Advisory
First Time		Isc bind Isc
CPE		cpe:2.3:a:isc:bind:::::-:::*

20 May 2026, 13:16

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-05-20 13:16

Updated : 2026-05-21 15:24

NVD link : CVE-2026-5950

Mitre link : CVE-2026-5950

CVE.ORG link : CVE-2026-5950

JSON object : View

Products Affected

isc

bind

CWE

CWE-606

Unchecked Input for Loop Condition

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