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CVE-2017-6519: Avahi: Information disclosure

CVE-2017-6519 is rated critical with a CVSS v3.0 base score of 9.1 and affects Avahi, along with 1 other product in NVD’s configuration data. Per its scoring, it can be exploited over the network, without authentication, without any user interaction.

Vulnerability description

avahi-daemon in Avahi through 0.6.32 and 0.7 inadvertently responds to IPv6 unicast queries with source addresses that are not on-link, which allows remote attackers to cause a denial of service (traffic amplification) and may cause information leakage by obtaining potentially sensitive information from the responding device via port-5353 UDP packets. NOTE: this may overlap CVE-2015-2809.

Severity breakdown

CVSS v3.0 9.1: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H

Attack vector: Network. Exploitable remotely over the network, with no need for local or physical access.
Attack complexity: Low. No special conditions; the attack can be repeated reliably.
Privileges required: None. No account or prior access is needed.
User interaction: None. No action from any user is needed.
Scope: Unchanged. Impact stays within the vulnerable component.
Confidentiality impact: High. Total loss of confidentiality; sensitive data can be fully disclosed.
Integrity impact: None. No loss of integrity.
Availability impact: High. Total loss of availability; the component can be shut down.

Underlying weakness

CWE-346: Origin Validation Error

The product does not properly verify that the source of data or communication is valid.

Affected products

Avahi: up to and including 0.6.32; 0.7
Canonical Ubuntu Linux: 12.04; 14.04; 16.04; 18.04; 18.10