CVE-2023-4236

named may terminate unexpectedly under high DNS-over-TLS query load

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.

Remediation

Solution:

  • Upgrade to the patched release most closely related to your current version of BIND 9: 9.18.19 or 9.18.19-S1.

Workaround:

  • Disabling listening for DNS-over-TLS connections (by removing `listen-on ... tls ... { ... };` statements from the configuration) prevents the affected code paths from being taken, rendering exploitation impossible. However, there is no workaround for this flaw if DNS-over-TLS support is required.

Category

7.5
CVSS
Severity: High
CVSS 3.1 •
EPSS 0.13%
Vendor Advisory isc.org
Affected: ISC BIND 9
Published at:
Updated at:

References

Link Tags
https://kb.isc.org/docs/cve-2023-4236 vendor advisory
http://www.openwall.com/lists/oss-security/2023/09/20/2 third party advisory mailing list
https://www.debian.org/security/2023/dsa-5504 third party 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://security.netapp.com/advisory/ntap-20231013-0004/ third party advisory
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/VSK5V4W4OHPM3JTJGWAQD6CZW7SFD75B/ third party advisory mailing list

Frequently Asked Questions

What is the severity of CVE-2023-4236?
CVE-2023-4236 has been scored as a high severity vulnerability.
How to fix CVE-2023-4236?
To fix CVE-2023-4236: Upgrade to the patched release most closely related to your current version of BIND 9: 9.18.19 or 9.18.19-S1.
Is CVE-2023-4236 being actively exploited in the wild?
As for now, there are no information to confirm that CVE-2023-4236 is being actively exploited. According to its EPSS score, there is a ~0% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2023-4236?
CVE-2023-4236 affects ISC BIND 9.
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