CVE-2024-8508

Publication date 3 October 2024

Last updated 19 December 2024

Ubuntu priority

Cvss 3 Severity Score

NLnet Labs Unbound up to and including version 1.21.0 contains a vulnerability when handling replies with very large RRsets that it needs to perform name compression for. Malicious upstreams responses with very large RRsets can cause Unbound to spend a considerable time applying name compression to downstream replies. This can lead to degraded performance and eventually denial of service in well orchestrated attacks. The vulnerability can be exploited by a malicious actor querying Unbound for the specially crafted contents of a malicious zone with very large RRsets. Before Unbound replies to the query it will try to apply name compression which was an unbounded operation that could lock the CPU until the whole packet was complete. Unbound version 1.21.1 introduces a hard limit on the number of name compression calculations it is willing to do per packet. Packets that need more compression will result in semi-compressed packets or truncated packets, even on TCP for huge messages, to avoid locking the CPU for long. This change should not affect normal DNS traffic.

Status

Show unmaintained releases

Package	Ubuntu Release	Status
unbound	24.10 oracular	Fixed 1.20.0-1ubuntu2.1
	24.04 LTS noble	Fixed 1.19.2-1ubuntu3.3
	22.04 LTS jammy	Fixed 1.13.1-1ubuntu5.8
	20.04 LTS focal	Fixed 1.9.4-2ubuntu1.9
	18.04 LTS bionic	Fixed 1.6.7-1ubuntu2.6+esm3 Ubuntu Pro
	16.04 LTS xenial	Fixed 1.5.8-1ubuntu1.1+esm2 Ubuntu Pro
	14.04 LTS trusty	Fixed 1.4.22-1ubuntu4.14.04.3+esm2 Ubuntu Pro

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Severity score breakdown

Parameter	Value
Base score	5.3 · Medium
Attack vector	Network
Attack complexity	Low
Privileges required	None
User interaction	None
Scope	Unchanged
Confidentiality	None
Integrity impact	None
Availability impact	Low
Vector	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

References

Related Ubuntu Security Notices (USN)

USN-7080-1
Unbound vulnerability
22 October 2024