CVE-2026-5950

5.3 MEDIUM
Published: May 20, 2026 Modified: May 21, 2026
View on NVD

Description

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.

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CVSS v3.x Details

0.0 Low Medium High Critical 10.0
Vector String
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

References to Advisories, Solutions, and Tools

Patch Vendor Advisory Exploit Third Party Advisory
https://downloads.isc.org/isc/bind9/9.18.49
Source: security-officer@isc.org
Patch
https://downloads.isc.org/isc/bind9/9.20.23
Source: security-officer@isc.org
Patch
https://downloads.isc.org/isc/bind9/9.21.22
Source: security-officer@isc.org
Patch
https://kb.isc.org/docs/cve-2026-5950
Source: security-officer@isc.org
Vendor Advisory

4 reference(s) from NVD

Quick Stats

CVSS v3 Score
5.3 / 10.0
EPSS (Exploit Probability)
0.5%
39th percentile
Exploitation Status
Not in CISA KEV

Weaknesses (CWE)

Affected Vendors

isc