A use-after-free vulnerability exists within the DNS-over-HTTPS implementation.
This issue affects BIND 9 versions 9.20.0 through 9.20.22, 9.21.0 through 9.21.21, and 9.20.9-S1 through 9.20.22-S1.
BIND 9 versions 9.18.0 through 9.18.48 and 9.18.11-S1 through 9.18.48-S1 are NOT affected.
Attack Parameters
Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Privileges Required
None
No privileges needed
User Interaction
None
No user interaction needed
Impact Assessment
Confidentiality
High
Complete data leak
Integrity
High
Complete data modification
Availability
High
Complete denial of service
CVSS Vector v3.1
Weakness Type (CWE)
Vulnerable Products 2
| Configuration | From (including) | Up to (excluding) |
|---|---|---|
|
Isc Bind
cpe:2.3:a:isc:bind:*:*:*:*:-:*:*:*
|
9.20.0
|
9.20.23
|
|
Isc Bind
cpe:2.3:a:isc:bind:*:*:*:*:-:*:*:*
|
9.21.0
|
9.21.22
|
References 7
https://downloads.isc.org/isc/bind9/9.20.23
security-officer@isc.org
https://downloads.isc.org/isc/bind9/9.21.22
security-officer@isc.org
https://kb.isc.org/docs/cve-2026-3593
security-officer@isc.org
https://access.redhat.com/errata/RHSA-2026:7412
0b0ca135-0b70-47e7-9f44-1890c2a1c46c
https://access.redhat.com/security/cve/CVE-2026-3593
0b0ca135-0b70-47e7-9f44-1890c2a1c46c
https://bugzilla.redhat.com/show_bug.cgi?id=2479770
0b0ca135-0b70-47e7-9f44-1890c2a1c46c
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-3593.json
0b0ca135-0b70-47e7-9f44-1890c2a1c46c