What’s Vulnerable › Vulnerabilities
CVE-2023-4236: named may terminate unexpectedly under high DNS-over-TLS query load
- Severity: high (CVSS 7.5 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 2.2% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2023-09-20 · updated 2026-06-17
- Weakness: CWE-617
Description
A flaw in the networking code handling DNS-over-TLS queries may cause `named` to terminate unexpectedly due to an assertion failure. This happens when internal data structures are incorrectly reused under significant DNS-over-TLS query load. This issue affects BIND 9 versions 9.18.0 through 9.18.18 and 9.18.11-S1 through 9.18.18-S1.
Affected products
- Debian Linux: 10.0, 11.0
- Fedoraproject Fedora: 37, 38, 39
- ISC BIND: from 9.18.0 before 9.18.18; 9.18.11-s1, 9.18.18-s1 — fixed in 9.18.18
- NetApp H300S Firmware: all versions
- NetApp H410C Firmware: all versions
- NetApp H410S Firmware: all versions
- NetApp H500S Firmware: all versions
- NetApp H700S Firmware: all versions
How to fix
Upgrade to a fixed version: ISC BIND 9.18.18. Check the vendor advisory for mitigations.
References
- http://www.openwall.com/lists/oss-security/2023/09/20/2
- https://kb.isc.org/docs/cve-2023-4236
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/IPJLLTJCSDJJII7IIZPLTBQNWP7MZH7F/
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/U35OARLQCPMVCBBPHWBXY5M6XJLD2TZ5/
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/VSK5V4W4OHPM3JTJGWAQD6CZW7SFD75B/
- https://security.netapp.com/advisory/ntap-20231013-0004/
- https://www.debian.org/security/2023/dsa-5504
- http://www.openwall.com/lists/oss-security/2023/09/20/2
- https://kb.isc.org/docs/cve-2023-4236
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/IPJLLTJCSDJJII7IIZPLTBQNWP7MZH7F/
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/U35OARLQCPMVCBBPHWBXY5M6XJLD2TZ5/
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/VSK5V4W4OHPM3JTJGWAQD6CZW7SFD75B/
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