CVE-2026-3104 Memory leak in code preparing DNSSEC proofs of non-existence

High 7.5 Published 25 Mar 2026 Updated 1 Sep 2026

A specially crafted domain query causes a memory leak in the BIND resolver, potentially leading to denial of service.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Over the internet
Victim action needed: Not needed
Fix: Available

What is CVE-2026-3104?

CVE-2026-3104 is a high-severity denial of service vulnerability in Isc Bind, published on 25 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

A specially crafted domain can be used to cause a memory leak in a BIND resolver simply by querying this domain. This issue affects BIND 9 versions 9.20.0 through 9.20.20, 9.21.0 through 9.21.19, and 9.20.9-S1 through 9.20.20-S1. BIND 9 versions 9.18.0 through 9.18.46 and 9.18.11-S1 through 9.18.46-S1 are NOT affected.

Weakness: CWE-401, CWE-772

Which versions are affected by CVE-2026-3104?

It affects 1 product.

Products include Isc Bind.

How do I fix CVE-2026-3104?

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-2026-3104 being exploited?

There is no known exploitation of CVE-2026-3104 in the wild and no public exploit code.

All Isc Bind vulnerabilities

Sources

Also known as ALPINE-CVE-2026-3104, AZL-80981, BELL-CVE-2026-3104, DEBIAN-CVE-2026-3104, GHSA-vwv5-298p-pw28, MINI-3xp5-2j53-r79r and 1 more.