Vulnerability Report

CVE-2026-3593

Title: Use-after-free in BIND DNS-over-HTTPS

Other

Proof Of Concept

No public PoC currently indexed for CVE-2026-3593.

CWE Category CWE-416

Published Date May 20, 2026

Modified Date Jul 24, 2026

Exploit Status Not Found

Score 7.4 CVSS v3.1

Exploit Probability (EPSS)

1.54%

Vulnerability Summary

CVE-2026-3593: 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.

Impacted Vendors

isc 1

Reference Links

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

CVSS v3.1

Source Entity [email protected]

Severity HIGH

7.4

Attack Vector

NETWORK

Complexity

HIGH

Privileges

N/A

Interaction

NONE

Confidentiality

N/A

Integrity

N/A

Availability

N/A

Scope

UNCHANGED

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

CVSS v3.1

Source Entity [email protected]

Severity CRITICAL

9.8

Attack Vector

NETWORK

Complexity

LOW

Privileges

N/A

Interaction

NONE

Confidentiality

N/A

Integrity

N/A

Availability

N/A

Scope

UNCHANGED

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

CVSS v3.1

Source Entity 0b0ca135-0b70-47e7-9f44-1890c2a1c46c

Severity HIGH

7.4

Attack Vector

NETWORK

Complexity

HIGH

Privileges

N/A

Interaction

NONE

Confidentiality

N/A

Integrity

N/A

Availability

N/A

Scope

UNCHANGED

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

Associated Attack Patterns (CAPEC)

Total: Patterns