# CVE-2026-96888: BIND assertion failure with redirect zone and qname-minimization

Source: https://junglewise.ai/threats/cve-2026-96888-a-bind-resolver-that-is-configured-with-both-a-redirect-zone-and  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-21. Updated: 2026-10-21  
License: CC BY 4.0 with a link back

CVE-2026-96888 · Severity: high · CVSS 7.5 · Published 2026-10-21

BIND is DNS resolver software used by organizations worldwide to perform DNS lookups. When configured with both a redirect zone and strict qname minimization, BIND can crash unexpectedly due to an assertion failure, causing DNS services to become unavailable and disrupting network connectivity for dependent systems and applications.

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

## Quick answers

**Is CVE-2026-96888 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-96888 being exploited in the wild.

**How severe is CVE-2026-96888?** High severity, with a CVSS score of 7.5, published 21 October 2026.

**Which products and versions are affected?** Isc Bind 9.16.0–9.18.50, 9.20.0–9.20.29, 9.21.0–9.21.26, 9.16.8-S1–9.18.50-S1, 9.20.9-S1–9.20.29-S1.

**Is there a fix for CVE-2026-96888?** Yes: fixed in BIND 9.18.51, 9.20.30, 9.21.27. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-96888 attacked?** It is attacked over the network.

**Am I affected by CVE-2026-96888?** Check whether you run Isc Bind 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.

## How to fix

- Fixed in BIND 9.18.51, 9.20.30, 9.21.27

## Technical details

An assertion failure occurs in BIND resolvers configured with both "redirect" zones and "qname-minimization strict" enabled during redirect processing. The vulnerability affects specific BIND 9 version ranges across stable (9.16.0–9.18.50, 9.20.0–9.20.29, 9.21.0–9.21.26) and ESV (Extended Support Version) branches. A network attacker can trigger this condition through specially crafted DNS queries, resulting in resolver process termination and denial of service.

## Affected products

- ISC BIND 9.16.0–9.18.50, 9.20.0–9.20.29, 9.21.0–9.21.26, 9.16.8-S1–9.18.50-S1, 9.20.9-S1–9.20.29-S1

## Timeline

- 2026-10-21: disclosed

## References

- [https://downloads.isc.org/isc/bind9/9.20.30](https://downloads.isc.org/isc/bind9/9.20.30)
- [https://downloads.isc.org/isc/bind9/9.21.27](https://downloads.isc.org/isc/bind9/9.21.27)

## Related threats

- [BIND named GSS-TSIG replay heap corruption](https://junglewise.ai/threats/cve-2026-94300-replaying-gss-tsig-signed-udp-messages-can-result-in-memory)
- [ISC BIND resolver DNS message processing denial of service](https://junglewise.ai/threats/cve-2026-19630-in-a-bind-resolver-inbound-dns-protocol-messages-with-a)
- [ISC BIND denial of service via TKEY queries](https://junglewise.ai/threats/cve-2015-5477-isc-bind-data-processing-errors-vulnerability)
- [BIND resolver crash on DNSSEC-signed wildcard with NSEC mismatch](https://junglewise.ai/threats/cve-2026-80274-bind-resolver-crash-on-dnssec-signed-wildcard-with-nsec-mismatch)
- [ISC BIND DNSSEC validation bypass with NSEC3 forgery](https://junglewise.ai/threats/cve-2026-77119-isc-bind-dnssec-validation-bypass-with-nsec3-forgery)