CVE-2023-4236

Name: CVE-2023-4236
Creator: NVD / NIST
Published: 2023-09-20T13:15:12.313+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.5/10EPSS 2.15%

Last modified Jun 17, 2026

CVE-2023-4236 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. 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.. EPSS estimates a 2.15% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1

7.5/10

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

EPSS Probability

2.15%

79.8th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-617

Affected Software

Vendor	Product	Versions	Update
Isc	Bind	>= 9.18.0, < 9.18.18	—
Isc	Bind	9.18.11	S1
Isc	Bind	9.18.18	S1
Fedoraproject	Fedora	37	—
Fedoraproject	Fedora	38	—
Fedoraproject	Fedora	39	—
Debian	Debian Linux	10.0	—
Debian	Debian Linux	11.0	—
Netapp	H300s Firmware	All versions	—
Netapp	H500s Firmware	All versions	—
Netapp	H700s Firmware	All versions	—
Netapp	H410s Firmware	All versions	—
Netapp	H410c Firmware	All versions	—

References

http://www.openwall.com/lists/oss-security/2023/09/20/2Mailing List, Third Party Advisory
https://kb.isc.org/docs/cve-2023-4236Vendor Advisory
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/IPJLLTJCSDJJII7IIZPLTBQNWP7MZH7F/Mailing List
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/U35OARLQCPMVCBBPHWBXY5M6XJLD2TZ5/Mailing List
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/VSK5V4W4OHPM3JTJGWAQD6CZW7SFD75B/Mailing List, Third Party Advisory
https://security.netapp.com/advisory/ntap-20231013-0004/Third Party Advisory
https://www.debian.org/security/2023/dsa-5504Third Party Advisory
http://www.openwall.com/lists/oss-security/2023/09/20/2Mailing List, Third Party Advisory
https://kb.isc.org/docs/cve-2023-4236Vendor Advisory
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/IPJLLTJCSDJJII7IIZPLTBQNWP7MZH7F/Mailing List
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/U35OARLQCPMVCBBPHWBXY5M6XJLD2TZ5/Mailing List
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/VSK5V4W4OHPM3JTJGWAQD6CZW7SFD75B/Mailing List, Third Party Advisory
https://security.netapp.com/advisory/ntap-20231013-0004/Third Party Advisory
https://www.debian.org/security/2023/dsa-5504Third Party Advisory

Timeline

Published: Sep 20, 2023
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2023-4236?

How severe is CVE-2023-4236?

CVE-2023-4236 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 2.15% probability of exploitation in the next 30 days.

How do I fix CVE-2023-4236?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2023-4236?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST