Is CVE-2026-123577 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-123577 being exploited in the wild.

How severe is CVE-2026-123577?

High severity, with a CVSS score of 7.5, published 8 November 2026.

Which products and versions are affected?

Hickory-Dns Hickory DNS 0.24.0 before 0.26.2.

Is there a fix for CVE-2026-123577?

Yes: fixed in 0.26.2. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-123577 attacked?

It is attacked over the network, in a software library.

Am I affected by CVE-2026-123577?

Check whether you run Hickory-Dns Hickory DNS 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-2026-123577: Hickory DNS resource exhaustion in DoH request buffering

CVE-2026-123577 · Severity: high · CVSS 7.5 · Published 2026-11-08

Hickory DNS is a DNS resolver library used in DNS over HTTP (DoH) servers. A remote attacker can send large HTTP/2 or HTTP/3 requests to exhaust server memory without any size limits, causing the DNS service to become unavailable and preventing legitimate DNS queries from being processed.

Technologies: Hickory-Dns Hickory DNS. Vendors: Hickory-Dns.

Quick answers

Is CVE-2026-123577 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-123577 being exploited in the wild.
How severe is CVE-2026-123577?: High severity, with a CVSS score of 7.5, published 8 November 2026.
Which products and versions are affected?: Hickory-Dns Hickory DNS 0.24.0 before 0.26.2.
Is there a fix for CVE-2026-123577?: Yes: fixed in 0.26.2. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-123577 attacked?: It is attacked over the network, in a software library.
Am I affected by CVE-2026-123577?: Check whether you run Hickory-Dns Hickory DNS 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: 0.26.2

Technical details

The vulnerability is an uncontrolled resource consumption issue in DoH request body buffering. When Hickory DNS processes DNS over HTTP requests via HTTP/2 or HTTP/3, it buffers the entire request body in memory without enforcing any size limits, allowing an attacker to send arbitrarily large payloads to exhaust memory and trigger denial of service. The fix is available in version 0.26.2.

Affected products

Hickory DNS hickory-dns 0.24.0 before 0.26.2

Timeline

2026-09-03: disclosed
2026-11-08: advisory

References

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