What is CVE-2026-3593?

CVE-2026-3593 is a high-severity vulnerability in Isc Bind, classified under Use After Free. CVSS score: 7.4/10. Published 2026-05-20.

How severe is CVE-2026-3593?

High severity. CVSS v3 base score is 7.4 out of 10.

Use After Free in Isc Bind

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…

Vulnerability class: Use-After-Free

EPSS: 0.000 (11.6th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 7.4 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:H.

Affected products

Isc Bind
Isc Bind 9 — versions 9.20.0, 9.21.0, 9.20.9-S1

Weakness classification (CWE)

CWE-416 — Use After Free

References

security-officer@isc.org (Patch, patch)
security-officer@isc.org (Patch, patch)
security-officer@isc.org (vendor-advisory, Vendor Advisory)

Frequently asked questions

What is CVE-2026-3593?: CVE-2026-3593 is a high-severity vulnerability in Isc Bind, classified under Use After Free. CVSS score: 7.4/10. Published 2026-05-20.
How severe is CVE-2026-3593?: High severity. CVSS v3 base score is 7.4 out of 10.