# CVE-2026-10723: ISC BIND incorrect NSEC3 record validation

Source: https://junglewise.ai/threats/cve-2026-10723-isc-bind-incorrect-nsec3-record-validation  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-07-22. Updated: 2026-07-22  
License: CC BY 4.0 with a link back

CVE-2026-10723 · Severity: medium · CVSS 6.8 · Published 2026-07-22

BIND is a widely used software suite for managing the Domain Name System (DNS), which translates human-readable web addresses into IP addresses. A vulnerability has been identified where BIND may incorrectly validate security records from child zones. This could allow a remote attacker to forge responses that falsely claim a legitimate website or service does not exist, potentially disrupting access to digital services or redirecting traffic.

Technologies: [Isc BIND 9](https://junglewise.ai/threats/technologies/bind-9). Vendors: [Isc](https://junglewise.ai/threats/vendors/isc).

## Quick answers

**Is CVE-2026-10723 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-10723 being exploited in the wild.

**How severe is CVE-2026-10723?** Medium severity, with a CVSS score of 6.8, published 22 July 2026.

**Which products and versions are affected?** Isc BIND 9 9.18.0 through 9.18.50, 9.20.0 through 9.20.24, 9.21.0 through 9.21.23, 9.11.3-S1 through 9.18.50-S1, 9.20.9-S1 through 9.20.24-S1.

**Is there a fix for CVE-2026-10723?** A patch was published on 2026-07-22: Fixed versions released Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-10723 attacked?** It is attacked over the network, in a hosted service.

**Am I affected by CVE-2026-10723?** Check whether you run Isc BIND 9 at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

A vulnerability exists in BIND 9's handling of DNSSEC NSEC3 records. The software may incorrectly accept NSEC3 records from a child zone as valid even when they are malformed or incorrect. An unauthenticated remote attacker can exploit this by providing forged NSEC3 records, allowing them to generate authenticated NXDOMAIN (non-existent domain) responses for sibling zones. This is classified as a cryptographic signature verification failure (CWE-347). The attack requires specific timing or network conditions (AC:H) but can impact the integrity of DNS data across security boundaries. Patches are available in versions 9.20.26, 9.21.24, and 9.20.26-S1.

## Affected products

- ISC BIND 9 9.18.0 through 9.18.50, 9.20.0 through 9.20.24, 9.21.0 through 9.21.23, 9.11.3-S1 through 9.18.50-S1, 9.20.9-S1 through 9.20.24-S1

## Timeline

- 2026-07-15: other: Early notification issued
- 2026-07-22: advisory: Public disclosure of CVE-2026-10723
- 2026-07-22: patched: Fixed versions released

## References

- [https://downloads.isc.org/isc/bind9/9.20.26](https://downloads.isc.org/isc/bind9/9.20.26)
- [https://downloads.isc.org/isc/bind9/9.21.24](https://downloads.isc.org/isc/bind9/9.21.24)
- [https://kb.isc.org/docs/cve-2026-10723](https://kb.isc.org/docs/cve-2026-10723)

## Related threats

- [ISC BIND recursive server assert failure denial of service](https://junglewise.ai/threats/cve-2026-97313-a-recursive-bind-server-that-receives-a-query-with-recursion)
- [ISC BIND DNSSEC validation bypass in NSEC records](https://junglewise.ai/threats/cve-2026-13321-isc-bind-dnssec-validation-bypass-in-nsec-records)
- [ISC BIND 9 denial of service via NSEC and NSEC3 assertion failure](https://junglewise.ai/threats/cve-2026-13204-isc-bind-9-denial-of-service-via-nsec-and-nsec3-assertion-failure)
- [ISC BIND 9 denial of service via CNAME or DNAME record ordering](https://junglewise.ai/threats/cve-2026-12617-isc-bind-9-denial-of-service-via-cname-or-dname-record-ordering)
- [ISC BIND 9 cache poisoning via RRSIG label count discrepancy](https://junglewise.ai/threats/cve-2026-11721-isc-bind-9-cache-poisoning-via-rrsig-label-count-discrepancy)