Is CVE-2026-3104 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-3104 being exploited in the wild.

How severe is CVE-2026-3104?

High severity, with a CVSS score of 7.5, published 25 March 2026.

Which products and versions are affected?

Isc BIND 9 9.20.0 through 9.20.20, 9.21.0 through 9.21.19, 9.20.9-S1 through 9.20.20-S1.

Is there a fix for CVE-2026-3104?

A patch was published on 2026-03-25: Patched versions 9.20.21 and 9.21.20 released Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-3104 attacked?

It is attacked over the network, in a hosted service.

Am I affected by CVE-2026-3104?

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.

CVE-2026-3104: ISC BIND 9 memory leak in DNSSEC proof-of-non-existence code

CVE-2026-3104 · Severity: high · CVSS 7.5 · Published 2026-03-25

BIND 9 is a widely used software suite for managing Domain Name System (DNS) services. A vulnerability in its resolver component allows an attacker to cause a memory leak by requesting information about a specially crafted domain. Over time, this can exhaust the server's available memory, leading to a service crash or system instability, effectively knocking the DNS server offline.

Technologies: Isc BIND 9. Vendors: Isc.

Quick answers

Is CVE-2026-3104 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-3104 being exploited in the wild.
How severe is CVE-2026-3104?: High severity, with a CVSS score of 7.5, published 25 March 2026.
Which products and versions are affected?: Isc BIND 9 9.20.0 through 9.20.20, 9.21.0 through 9.21.19, 9.20.9-S1 through 9.20.20-S1.
Is there a fix for CVE-2026-3104?: A patch was published on 2026-03-25: Patched versions 9.20.21 and 9.21.20 released Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-3104 attacked?: It is attacked over the network, in a hosted service.
Am I affected by CVE-2026-3104?: 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 memory leak exists in BIND 9 within the code responsible for preparing DNSSEC proofs of non-existence. The vulnerability is classified as a missing release of memory (CWE-401/CWE-772) and can be triggered remotely by an unauthenticated attacker who sends a query for a specially crafted domain to an affected BIND resolver. This results in unbounded growth of Resident Set Size (RSS) memory, eventually causing an out-of-memory (OOM) condition. Additionally, the 'named' process will exit with an assertion failure if a shutdown or reload is attempted while in this state. Authoritative-only servers are generally unaffected. Patches are available in versions 9.20.21 and 9.21.20.

Affected products

ISC BIND 9 9.20.0 through 9.20.20, 9.21.0 through 9.21.19, 9.20.9-S1 through 9.20.20-S1

Timeline

2026-03-18: other: Early notification provided
2026-03-25: disclosed: Public disclosure and advisory published
2026-03-25: patched: Patched versions 9.20.21 and 9.21.20 released

References

This page as Markdown. Free to reuse under CC BY 4.0 with a link back.