Use-After-Free Vulnerability in BIND 9 by Internet Systems Consortium
CVE-2026-3593

7.4HIGH

Key Information:

Vendor

Isc
Status
Bind 9
Vendor
CVE Published:
20 May 2026

Badges

👾 Exploit Exists

What is CVE-2026-3593?

A use-after-free vulnerability has been identified in the DNS-over-HTTPS implementation of BIND 9, affecting several versions. This flaw can lead to various security issues, potentially allowing unauthorized access or manipulation of data. Users of BIND 9 should ensure they are running the latest patched versions to mitigate this concern.

Affected Version(s)

BIND 9 9.20.0 <= 9.20.22

BIND 9 9.21.0 <= 9.21.21

BIND 9 9.20.9-S1 <= 9.20.22-S1

References

https://kb.isc.org/docs/cve-2026-3593
vendor-advisory
https://downloads.isc.org/isc/bind9/9.20.23
patch
https://downloads.isc.org/isc/bind9/9.21.22
patch

CVSS V3.1

Score:
7.4
Severity:
HIGH
Confidentiality:
High
Integrity:
None
Availability:
High
Attack Vector:
Network
Attack Complexity:
High
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • 👾

    Exploit known to exist

  • Vulnerability published

  • Vulnerability Reserved

Credit

ISC would like to thank Naresh Kandula Parmar (Nottiboy) for bringing this vulnerability to our attention.
.