CVE-2026-3593

Name: CVE-2026-3593
Creator: NVD / NIST
Published: 2026-05-20T13:16:23.923+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

CRITICALCVSS 9.8/10EPSS 1.64%

Last modified Jun 17, 2026

CVE-2026-3593 is a critical-severity vulnerability rated 9.8/10 on the CVSS scale. A use-after-free vulnerability exists within the DNS-over-HTTPS implementation. This issue affects BIND 9 versions 9.20.0 through 9.20.22, 9.21.0 through 9.21.21, and 9.20.9-S1 through 9.20.22-S1. BIND 9 versions 9.18.0 through 9.18.48 and 9.18.11-S1 through 9.18.48-S1 are NOT affected.. EPSS estimates a 1.64% chance of exploitation in the next 30 days.

Description

A use-after-free vulnerability exists within the DNS-over-HTTPS implementation. This issue affects BIND 9 versions 9.20.0 through 9.20.22, 9.21.0 through 9.21.21, and 9.20.9-S1 through 9.20.22-S1. BIND 9 versions 9.18.0 through 9.18.48 and 9.18.11-S1 through 9.18.48-S1 are NOT affected.

Metrics

CVSS 3.1

9.8/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS Probability

1.64%

73.4th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-416

Affected Software

Vendor	Product	Versions
Isc	Bind	>= 9.20.0, < 9.20.23
Isc	Bind	>= 9.21.0, < 9.21.22

References

https://downloads.isc.org/isc/bind9/9.20.23Patch
https://downloads.isc.org/isc/bind9/9.21.22Patch
https://kb.isc.org/docs/cve-2026-3593Vendor Advisory

Timeline

Published: May 20, 2026
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2026-3593?

How severe is CVE-2026-3593?

CVE-2026-3593 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 1.64% probability of exploitation in the next 30 days.

How do I fix CVE-2026-3593?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2026-3593?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST