CVE-2026-3593: CWE-416 Use After Free in ISC BIND 9
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.
AI Analysis
Technical Summary
This vulnerability (CVE-2026-3593) involves a use-after-free condition in the DNS-over-HTTPS component of ISC BIND 9, a widely used DNS server software. It affects specific versions starting from 9.20.0 up to 9.21.21 and their respective S1 variants, but not earlier 9.18.x versions. The issue could allow an attacker to cause a denial of service due to memory corruption. The CVSS v3.1 score is 7.4, reflecting network attack vector, high complexity, no privileges required, no user interaction, unchanged scope, high confidentiality impact, no integrity impact, and high availability impact. No patch or official remediation level has been published by ISC as of the provided data.
Potential Impact
The vulnerability can lead to a denial of service condition by exploiting a use-after-free flaw in the DNS-over-HTTPS implementation, potentially causing the affected BIND 9 server to crash or become unavailable. Confidentiality impact is rated high by CVSS, but integrity impact is not affected. There are no known active exploits in the wild currently.
Mitigation Recommendations
Patch status is not yet confirmed — check the ISC vendor advisory for current remediation guidance. Until an official fix is available, consider avoiding affected versions or disabling DNS-over-HTTPS if feasible. Monitor ISC communications for updates on patches or workarounds.
CVE-2026-3593: CWE-416 Use After Free in ISC BIND 9
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.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
This vulnerability (CVE-2026-3593) involves a use-after-free condition in the DNS-over-HTTPS component of ISC BIND 9, a widely used DNS server software. It affects specific versions starting from 9.20.0 up to 9.21.21 and their respective S1 variants, but not earlier 9.18.x versions. The issue could allow an attacker to cause a denial of service due to memory corruption. The CVSS v3.1 score is 7.4, reflecting network attack vector, high complexity, no privileges required, no user interaction, unchanged scope, high confidentiality impact, no integrity impact, and high availability impact. No patch or official remediation level has been published by ISC as of the provided data.
Potential Impact
The vulnerability can lead to a denial of service condition by exploiting a use-after-free flaw in the DNS-over-HTTPS implementation, potentially causing the affected BIND 9 server to crash or become unavailable. Confidentiality impact is rated high by CVSS, but integrity impact is not affected. There are no known active exploits in the wild currently.
Mitigation Recommendations
Patch status is not yet confirmed — check the ISC vendor advisory for current remediation guidance. Until an official fix is available, consider avoiding affected versions or disabling DNS-over-HTTPS if feasible. Monitor ISC communications for updates on patches or workarounds.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- isc
- Date Reserved
- 2026-03-05T12:57:16.981Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a0db4daba1db473627ecd31
Added to database: 5/20/2026, 1:19:22 PM
Last enriched: 5/20/2026, 1:34:34 PM
Last updated: 5/20/2026, 4:36:07 PM
Views: 3
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