Ubuntu update for avahi
| Risk | Low |
| Patch available | YES |
| Number of vulnerabilities | 2 |
| CVE-ID | CVE-2021-3468 CVE-2021-3502 |
| CWE-ID | CWE-835 CWE-617 |
| Exploitation vector | Local |
| Public exploit | N/A |
| Vulnerable software |
Ubuntu Operating systems & Components / Operating system avahi-daemon (Ubuntu package) Operating systems & Components / Operating system package or component libavahi-core7 (Ubuntu package) Operating systems & Components / Operating system package or component |
| Vendor | Canonical Ltd. |
Security Bulletin
This security bulletin contains information about 2 vulnerabilities.
1) Infinite loop
EUVDB-ID: #VU79113
Risk: Low
CVSSv4.0: 4.3 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear]
CVE-ID: CVE-2021-3468
CWE-ID:
CWE-835 - Loop with Unreachable Exit Condition ('Infinite Loop')
Exploit availability: No
DescriptionThe vulnerability allows a local user to perform a denial of service (DoS) attack.
The vulnerability exists due to event used to signal the termination of the client connection on the avahi Unix socket is not correctly handled in the client_work() function. A local user can consume all available system resources and cause denial of service conditions.
MitigationUpdate the affected package avahi to the latest version.
Vulnerable software versionsUbuntu: 18.04 - 21.04
avahi-daemon (Ubuntu package): before 0.7-3.1ubuntu1.3
libavahi-core7 (Ubuntu package): before 0.7-3.1ubuntu1.3
CPE2.3- cpe:2.3:o:canonical:ubuntu:18.04:*:*:*:*:*:*:*
- cpe:2.3:o:canonical:ubuntu:20.04:*:*:*:*:*:*:*
- cpe:2.3:o:canonical:ubuntu:20.10:*:*:*:*:*:*:*
- cpe:2.3:o:canonical:ubuntu:21.04:*:*:*:*:*:*:*
- cpe:2.3:a:canonical:avahi-daemon_ubuntu_package:*:*:*:*:*:ubuntu:*:*
- cpe:2.3:a:canonical:libavahi-core7_ubuntu_package:*:*:*:*:*:ubuntu:*:*
https://ubuntu.com/security/notices/USN-5008-1
Q & A
Can this vulnerability be exploited remotely?
No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.
Is there known malware, which exploits this vulnerability?
No. We are not aware of malware exploiting this vulnerability.
2) Reachable Assertion
EUVDB-ID: #VU83306
Risk: Low
CVSSv4.0: 1.1 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:U/U:Clear]
CVE-ID: CVE-2021-3502
CWE-ID:
CWE-617 - Reachable Assertion
Exploit availability: No
DescriptionThe vulnerability allows a local user to perform a denial of service (DoS) attack.
The vulnerability exists due to a reachable assertion within the avahi_s_host_name_resolver_start function. A local user can pass specially crafted input to the application and perform a denial of service (DoS) attack.
Update the affected package avahi to the latest version.
Vulnerable software versionsUbuntu: 18.04 - 21.04
avahi-daemon (Ubuntu package): before 0.7-3.1ubuntu1.3
libavahi-core7 (Ubuntu package): before 0.7-3.1ubuntu1.3
CPE2.3- cpe:2.3:o:canonical:ubuntu:18.04:*:*:*:*:*:*:*
- cpe:2.3:o:canonical:ubuntu:20.04:*:*:*:*:*:*:*
- cpe:2.3:o:canonical:ubuntu:20.10:*:*:*:*:*:*:*
- cpe:2.3:o:canonical:ubuntu:21.04:*:*:*:*:*:*:*
- cpe:2.3:a:canonical:avahi-daemon_ubuntu_package:*:*:*:*:*:ubuntu:*:*
- cpe:2.3:a:canonical:libavahi-core7_ubuntu_package:*:*:*:*:*:ubuntu:*:*
https://ubuntu.com/security/notices/USN-5008-1
Q & A
Can this vulnerability be exploited remotely?
No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.
Is there known malware, which exploits this vulnerability?
No. We are not aware of malware exploiting this vulnerability.
