CVE-2026-80274 Validating resolver can abort while caching a mismatched NOQNAME proof
A remote attacker can cause a denial of service in BIND by sending crafted DNSSEC responses that trigger an unexpected program exit.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-80274?
CVE-2026-80274 is a high-severity denial of service vulnerability in ISC BIND 9, published on 16 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
If a BIND resolver sends a query for a DNSSEC-signed authoritative zone, and the authoritative server replies with a valid wildcard answer and signed NSEC3 proof, followed by an unsigned NSEC at the same owner name, it will trigger an unexpected program exit. This issue affects BIND 9 versions 9.11.0 through 9.18.50, 9.20.0 through 9.20.27, 9.21.0 through 9.21.25, 9.11.3-S1 through 9.18.50-S1, and 9.20.9-S1 through 9.20.27-S1.
Weakness: CWE-617
Which versions are affected by CVE-2026-80274?
How do I fix CVE-2026-80274?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-80274 being exploited?
There is no known exploitation of CVE-2026-80274 in the wild and no public exploit code.
Sources
Also known as ALPINE-CVE-2026-80274, AZL-103335, BELL-CVE-2026-80274, CLSA-2026-1790905625, CLSA-2026-1791226662, DEBIAN-CVE-2026-80274 and 7 more.