CVE-2023-4236

Publication date 20 September 2023

Last updated 4 August 2025

Ubuntu priority

Cvss 3 Severity Score

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.

Read the notes from the security team

Status

Show unmaintained releases

Package	Ubuntu Release	Status
bind9	25.04 plucky	Fixed 1:9.18.18-0ubuntu2
	24.10 oracular	Fixed 1:9.18.18-0ubuntu2
	24.04 LTS noble	Fixed 1:9.18.18-0ubuntu2
	23.10 mantic	Fixed 1:9.18.18-0ubuntu2
	23.04 lunar	Fixed 1:9.18.12-1ubuntu1.2
	22.04 LTS jammy	Fixed 1:9.18.12-0ubuntu0.22.04.3
	20.04 LTS focal	Not affected
	18.04 LTS bionic	Not affected
	16.04 LTS xenial	Not affected
	14.04 LTS trusty	Not affected
isc-dhcp	25.04 plucky	Not affected
	24.10 oracular	Not affected
	24.04 LTS noble	Not affected
	23.10 mantic	Not affected
	23.04 lunar	Not affected
	22.04 LTS jammy	Not affected
	20.04 LTS focal	Not affected
	18.04 LTS bionic	Not affected
	16.04 LTS xenial	Not affected
	14.04 LTS trusty	Not affected

Notes

alexmurray

As of isc-dhcp-4.4.3-1, isc-dhcp vendors bind9 libs

mdeslaur

9.18.x only

Severity score breakdown

Parameter	Value
Base score	7.5 · High
Attack vector	Network
Attack complexity	Low
Privileges required	None
User interaction	None
Scope	Unchanged
Confidentiality	None
Integrity impact	None
Availability impact	High
Vector	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References

Related Ubuntu Security Notices (USN)

USN-6390-1
Bind vulnerabilities
20 September 2023