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Several security issues were fixed in c-ares. Software Description: - c-ares: library for asynchronous name resolution Details: It was discovered that c-ares incorrectly parsed certain SOA replies. A remote attacker could possibly use this issue to cause c-ares to crash, resulting in a denial of service. This issue only affected Ubuntu 16.04 LTS and Ubuntu 18.04 LTS. (CVE-2020-22217) It was discovered that c-ares incorrectly handled certain sortlist strings. A remote attacker could possibly use this issue to cause c-ares to crash, resulting in a denial of service, or execute arbitrary code. This issue only affected Ubuntu 16.04 LTS. (CVE-2022-4904) It was discovered that c-ares did not properly limit DNS compression pointer hops or assembled name lengths when parsing DNS names. A remote attacker could possibly use this issue to cause c-ares to use excessive resources, resulting in a denial of service. (CVE-2026-69184) It was discovered that c-ares did not properly validate re... Read the Full Advisory
Several security issues were fixed in c-ares.
Software Description:
- c-ares: library for asynchronous name resolution
It was discovered that c-ares incorrectly parsed certain SOA replies. A
remote attacker could possibly use this issue to cause c-ares to crash,
resulting in a denial of service. This issue only affected Ubuntu 16.04 LTS
and Ubuntu 18.04 LTS. (CVE-2020-22217)
It was discovered that c-ares incorrectly handled certain sortlist strings.
A remote attacker could possibly use this issue to cause c-ares to crash,
resulting in a denial of service, or execute arbitrary code. This issue
only affected Ubuntu 16.04 LTS. (CVE-2022-4904)
It was discovered that c-ares did not properly limit DNS compression
pointer hops or assembled name lengths when parsing DNS names. A remote
attacker could possibly use this issue to cause c-ares to use excessive
resources, resulting in a denial of service. (CVE-2026-69184)
It was discovered that c-ares did not properly validate re...
The problem can be corrected by updating your system to the following package versions: Ubuntu 26.04 LTS libcares2 1.34.6-1ubuntu0.2 Ubuntu 24.04 LTS libcares2 1.27.0-1.0ubuntu1.1 Ubuntu 22.04 LTS libc-ares2 1.18.1-1ubuntu0.22.04.4 Ubuntu 20.04 LTS libc-ares2 1.15.0-1ubuntu0.5+esm1 Available with Ubuntu Pro Ubuntu 18.04 LTS libc-ares2 1.14.0-1ubuntu0.2+esm3 Available with Ubuntu Pro Ubuntu 16.04 LTS libc-ares2 1.10.0-3ubuntu0.2+esm4 Available with Ubuntu Pro In general, a standard system update will make all the necessary changes.
CVE-2020-22217, CVE-2022-4904, CVE-2026-69184, CVE-2026-69186
Ubuntu Security Notice USN-8951-1
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