# CVE-2026-83635: DNS Server out-of-bounds read denial of service

Source: https://junglewise.ai/threats/cve-2026-83635-out-of-bounds-read-in-dns-server-allows-an-unauthorized-attacker  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-13. Updated: 2026-10-16  
License: CC BY 4.0 with a link back

CVE-2026-83635 · Severity: high · CVSS 7.5 · Published 2026-10-13

A DNS server implementation contains an out-of-bounds read vulnerability that allows an attacker on the network to crash the service and prevent legitimate queries from being resolved. This can disrupt critical network services that depend on DNS for hostname resolution and service discovery.

Technologies: [Microsoft DNS Server](https://junglewise.ai/threats/technologies/microsoft-dns-server), [Microsoft Windows Server 2012](https://junglewise.ai/threats/technologies/windows-server-2012), [Microsoft Windows Server 2016](https://junglewise.ai/threats/technologies/windows-server-2016), [Microsoft Windows Server 2019](https://junglewise.ai/threats/technologies/windows-server-2019), [Microsoft Windows Server 2022](https://junglewise.ai/threats/technologies/windows-server-2022), [Microsoft Windows Server 2025](https://junglewise.ai/threats/technologies/windows-server-2025). Vendors: [Microsoft](https://junglewise.ai/threats/vendors/microsoft).

## Quick answers

**Is CVE-2026-83635 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-83635 being exploited in the wild.

**How severe is CVE-2026-83635?** High severity, with a CVSS score of 7.5, published 13 October 2026.

**Which products and versions are affected?** Microsoft DNS Server.

**Is there a fix for CVE-2026-83635?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-83635 attacked?** It is attacked over the network, in a hosted service.

**Am I affected by CVE-2026-83635?** Check whether you run Microsoft DNS Server, Microsoft Windows Server 2012, Microsoft Windows Server 2016 or one of the others listed. 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

An out-of-bounds read in DNS Server allows an unauthenticated attacker to trigger a denial of service by sending specially crafted DNS queries over the network. The vulnerability requires network access but no prior authentication. Exploitation results in service unavailability rather than data exposure.

## Affected products

- Microsoft DNS Server

## Timeline

- 2026-10-13: disclosed

## References

- [https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-83635](https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-83635)

## Related threats

- [Windows DNS Server out-of-bounds read](https://junglewise.ai/threats/cve-2026-97844-out-of-bounds-read-in-dns-server-allows-an-authorized-attacker-to)
- [Windows DNS Server out-of-bounds read information disclosure](https://junglewise.ai/threats/cve-2026-97843-out-of-bounds-read-in-dns-server-allows-an-authorized-attacker-to)
- [Windows DNS Server out-of-bounds read information disclosure](https://junglewise.ai/threats/cve-2026-97842-out-of-bounds-read-in-dns-server-allows-an-authorized-attacker-to)
- [Windows DNS Server out-of-bounds read](https://junglewise.ai/threats/cve-2026-97841-out-of-bounds-read-in-dns-server-allows-an-authorized-attacker-to)
- [DNS Server out-of-bounds read information disclosure](https://junglewise.ai/threats/cve-2026-97840-out-of-bounds-read-in-dns-server-allows-an-authorized-attacker-to)