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© 2026 FAUCET Technologies LLC. All rights reserved.

CVE-2026-3593

43
FAUCET Score

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.

First published: May 20, 2026Last modified: May 20, 2026

Impacted Technologies

VendorProductVersion(s)CPE
>= 9.20.0, < 9.20.23CPE matchmatch criteria
cpe:2.3:a:isc:bind:*:*:*:*:-:*:*:*
>= 9.21.0, < 9.21.22CPE matchmatch criteria
cpe:2.3:a:isc:bind:*:*:*:*:-:*:*:*

CVSS Data

CVSS version used by this source: 3.1

7.4HIGH

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

Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
NONE
Availability Impact
HIGH
Exploitability Score
2.2
Impact Score
5.2
CvssVersion
3.1

Exploit Intelligence

EPSS Score
1.54%
Probability of exploitation in next 30 days
EPSS Percentile
72.3%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0154 is in the 59th percentile among its peer group of 36,897 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.3 Bluesky, 0.3 Mastodon, and 2.4 GitHub mentions.

Media Mentions

The average CVE in this peer group has 0.3 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (6)

microsoftpatch availablevia msrc
Product: azl3 bind 9.20.21-1 on Azure Linux 3.0Fixed in: 9.20.23-1
microsoftpatch availablevia msrc
Product: 21351-17084Fixed in: 9.20.23-1
ubuntupatch availablevia ubuntu_usn
Product: bind9 (jammy)Fixed in: 1:9.18.39-0ubuntu0.22.04.4
ubuntupatch availablevia ubuntu_usn
Product: bind9 (noble)Fixed in: 1:9.18.39-0ubuntu0.24.04.5
ubuntupatch availablevia ubuntu_usn
Product: bind9 (questing)Fixed in: 1:9.20.11-1ubuntu2.4
ubuntupatch availablevia ubuntu_usn
Product: bind9 (resolute)Fixed in: 1:9.20.18-1ubuntu2.1

Vendor Advisories (2)

ubuntuUSN-8293-1

Bind vulnerabilities

May 21, 2026
microsoft2026-May/CVE-2026-3593Important

Heap use-after-free vulnerability in BIND 9 DNS-over-HTTPS implementation

May 12, 2026

References

access.redhat.com / errata/RHSA-2026:7412
access.redhat.com / security/cve/CVE-2026-3593
bugzilla.redhat.com / show_bug.cgi
security.access.redhat.com / data/csaf/v2/vex/2026/cve-2026-3593.json
downloads.isc.org / isc/bind9/9.20.23
Patch
downloads.isc.org / isc/bind9/9.21.22
Patch
kb.isc.org / docs/cve-2026-3593
Vendor Advisory