CVE-2026-3593

critical

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.

References

https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-3593.json

https://kb.isc.org/docs/cve-2026-3593

https://downloads.isc.org/isc/bind9/9.21.22

https://downloads.isc.org/isc/bind9/9.20.23

https://bugzilla.redhat.com/show_bug.cgi?id=2479770

https://access.redhat.com/security/cve/CVE-2026-3593

https://access.redhat.com/errata/RHSA-2026:7412

Details

Source: Mitre, NVD

Published: 2026-05-20

Updated: 2026-06-30

Risk Information

CVSS v2

Base Score: 10

Vector: CVSS2#AV:N/AC:L/Au:N/C:C/I:C/A:C

Severity: Critical

CVSS v3

Base Score: 9.8

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

Severity: Critical

EPSS

EPSS: 0.00024