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 9.18.11-S1 through 9.18.48-S1 are NOT affected.
Vulnerability class: Use-After-Free
Published · last modified .
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.
EPSS exploit prediction
EPSS: 0.011 (64.8th percentile), scored .
Low probability of exploitation in the next 30 days, but still tracked. 65th percentile — 64.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.015 · newest: 0.011 · change: -0.004
Affected products
- Isc Bind
- Isc Bind 9 — versions 9.20.0, 9.21.0, 9.20.9-S1
Weakness classification (CWE)
References
- downloads.isc.org/isc/bind9/9.20.23 (Patch, patch)
- downloads.isc.org/isc/bind9/9.21.22 (Patch, patch)
- CVE-2026-3593 (vendor-advisory, Vendor Advisory)
- 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
- 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
- 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
- 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
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.