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Ubuntu Security Notice USN-7239-1
January 28, 2025

libmicrodns vulnerabilities
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A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 18.04 LTS

Summary:

Several security issues were fixed in libmicrodns.

Software Description:
- libmicrodns: minimal mDNS resolver and announcer library

Details:

It was discovered that libmicrodns could recursively follow the same
compression pointer, leading to an infinite loop. An attacker could
possibly use this issue to cause a denial of service. (CVE-2020-6071)

It was discovered that libmicrodns did not check the return value of the
rr_decode function, which could lead to a double free. An attacker could
possibly use this issue to execute arbitrary code. (CVE-2020-6072)

It was discovered that libmicrodns incorrectly handled certain inputs,
which could lead to an integer overflow. An attacker could possibly use
this issue to cause a denial of service. (CVE-2020-6073)

It was discovered that libmicrodns incorrectly handled certain inputs,
which could lead to a out-of-bounds read. An attacker could possibly use
this issue to cause a denial of service. (CVE-2020-6077)

It was discovered that libmicrodns incorrectly handled memory when parsing
mDNS messages in mdns_recv, which could lead to a NULL pointer dereference.
An attacker could possibly use this issue to cause a denial of service.
(CVE-2020-6078)

It was discovered that libmicrodns incorrectly handled memory, which could
lead to excessive memory consumption due to memory leaks. An attacker
could possibly use this issue to cause a denial of service.
(CVE-2020-6079, CVE-2020-6080)

Update instructions:

The problem can be corrected by updating your system to the following
package versions:

Ubuntu 18.04 LTS
   libmicrodns0                    0.0.8-1ubuntu0.1~esm1
                                   Available with Ubuntu Pro

In general, a standard system update will make all the necessary changes.

References:
   https://ubuntu.com/security/notices/USN-7239-1
   CVE-2020-6071, CVE-2020-6072, CVE-2020-6073, CVE-2020-6077,
   CVE-2020-6078, CVE-2020-6079, CVE-2020-6080