Unexpected Exit Vulnerability in BIND Resolver by ISC
CVE-2026-19666

7.5HIGH

Key Information:

Vendor

Isc
Status
Bind 9
Vendor
CVE Published:
16 September 2026

Badges

👾 Exploit Exists

What is CVE-2026-19666?

A vulnerability exists in the BIND resolver when configured to use dns64. If the authoritative server returns a malformed response, it can cause the named process to exit unexpectedly. This could potentially disrupt DNS service and impact applications relying on DNS resolution.

Affected Version(s)

BIND 9 9.11.0 <= 9.18.50

BIND 9 9.20.0 <= 9.20.27

BIND 9 9.21.0 <= 9.21.25

References

https://kb.isc.org/docs/cve-2026-19666
vendor-advisory
https://downloads.isc.org/isc/bind9/9.20.29
patch
https://downloads.isc.org/isc/bind9/9.21.26
patch

CVSS V3.1

Score:
7.5
Severity:
HIGH
Confidentiality:
None
Integrity:
None
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • 👾

    Exploit known to exist

  • Vulnerability published

  • Vulnerability Reserved

Credit

ISC would like to thank Rintaro Kawasugi for bringing this vulnerability to our attention.
.