NSEC3 Acceptance Vulnerability in BIND DNS Software by ISC
CVE-2026-77119

5.9MEDIUM

Key Information:

Vendor

Isc
Status
Bind 9
Vendor
CVE Published:
16 September 2026

Badges

👾 Exploit Exists

What is CVE-2026-77119?

A vulnerability exists in BIND DNS software that allows a validly signed NSEC3 from an unrelated sibling zone to be accepted as an insecurity proof. This can potentially downgrade a secure delegation, leading to the acceptance of a forged unsigned answer, which compromises DNS integrity and security.

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-2026-77119
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:
5.9
Severity:
MEDIUM
Confidentiality:
None
Integrity:
High
Availability:
None
Attack Vector:
Network
Attack Complexity:
High
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • 👾

    Exploit known to exist

  • Vulnerability published

  • Vulnerability Reserved

.