CVE-2021-3502

Name: CVE-2021-3502
Creator: NVD / NIST
Published: 2021-05-07T12:15:07.267+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 5.5/10EPSS 0.37%

Last modified Jun 17, 2026

CVE-2021-3502 is a medium-severity vulnerability rated 5.5/10 on the CVSS scale. A flaw was found in avahi 0.8-5. A reachable assertion is present in avahi_s_host_name_resolver_start function allowing a local attacker to crash the avahi service by requesting hostname resolutions through the avahi socket or dbus methods for invalid hostnames. EPSS estimates a 0.37% chance of exploitation in the next 30 days.

Description

A flaw was found in avahi 0.8-5. A reachable assertion is present in avahi_s_host_name_resolver_start function allowing a local attacker to crash the avahi service by requesting hostname resolutions through the avahi socket or dbus methods for invalid hostnames. The highest threat from this vulnerability is to the service availability.

Metrics

CVSS 3.1

5.5/10

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

EPSS Probability

0.37%

29.2th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-617

Affected Software

Vendor	Product	Versions
Avahi	Avahi	0.8-5

References

https://bugzilla.redhat.com/show_bug.cgi?id=1946914Exploit, Issue Tracking, Patch, Third Party Advisory
https://github.com/lathiat/avahi/issues/338Exploit, Third Party Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=1946914Exploit, Issue Tracking, Patch, Third Party Advisory
https://github.com/lathiat/avahi/issues/338Exploit, Third Party Advisory

Timeline

Published: May 7, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-3502?

How severe is CVE-2021-3502?

CVE-2021-3502 has a CVSS score of 5.5/10 (MEDIUM severity). The EPSS model estimates a 0.37% probability of exploitation in the next 30 days.

How do I fix CVE-2021-3502?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-3502?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST