Public Date:
1426712: CVE-2017-6519 avahi: Multicast DNS responds to unicast queries outside of local network

The MITRE CVE dictionary describes this issue as:

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.

Find out more about CVE-2017-6519 from the MITRE CVE dictionary dictionary and NIST NVD.

CVSS v3 metrics

NOTE: The following CVSS v3 metrics and score provided are preliminary and subject to review.

CVSS3 Base Score 5.8
CVSS3 Base Metrics CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L
Attack Vector Network
Attack Complexity Low
Privileges Required None
User Interaction None
Scope Changed
Confidentiality None
Integrity Impact None
Availability Impact Low

Affected Packages State

Platform Package State
Red Hat Enterprise Linux 8 avahi Will not fix
Red Hat Enterprise Linux 7 avahi Will not fix
Red Hat Enterprise Linux 6 avahi Will not fix
Red Hat Enterprise Linux 5 avahi Will not fix


Ensure UDP port 5353 is blocked in the firewall. Moreover, configure correctly the rate limiting options based on your needs (see ratelimit-interval-usec and ratelimit-burst options in /etc/avahi/avahi-daemon.conf).

External References

Last Modified

CVE description copyright © 2017, The MITRE Corporation