QSN-8951-1: c-ares vulnerabilities
2026-10-21

Summary:
Several security issues were fixed in c-ares.

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 record count fields
before allocating memory when parsing DNS responses. A remote attacker
could possibly use this issue to cause c-ares to use excessive resources,
resulting in a denial of service. This issue only affected Ubuntu 24.04 LTS
and Ubuntu 26.04 LTS. (CVE-2026-69186)

Affected QuantaStor releases:
  6.9.1.001 jammy: libc-ares2 1.18.1-1ubuntu0.22.04.4 (fixed in 1.18.1-1ubuntu0.22.04.4)
  6.9.0.464 jammy: libc-ares2 1.18.1-1ubuntu0.22.04.3 (fixed in 1.18.1-1ubuntu0.22.04.4)
  6.8.6.015 jammy: libc-ares2 1.18.1-1ubuntu0.22.04.3 (fixed in 1.18.1-1ubuntu0.22.04.4)
  6.8.5.018 jammy: libc-ares2 1.18.1-1ubuntu0.22.04.3 (fixed in 1.18.1-1ubuntu0.22.04.4)
  6.8.4.038 jammy: libc-ares2 1.18.1-1ubuntu0.22.04.3 (fixed in 1.18.1-1ubuntu0.22.04.4)
  6.8.3.018 jammy: libc-ares2 1.18.1-1ubuntu0.22.04.3 (fixed in 1.18.1-1ubuntu0.22.04.4)
  6.8.2.002 jammy: libc-ares2 1.18.1-1ubuntu0.22.04.3 (fixed in 1.18.1-1ubuntu0.22.04.4)
  6.8.1.007 jammy: libc-ares2 1.18.1-1ubuntu0.22.04.3 (fixed in 1.18.1-1ubuntu0.22.04.4)
  6.8.0.205 jammy: libc-ares2 1.18.1-1ubuntu0.22.04.3 (fixed in 1.18.1-1ubuntu0.22.04.4)

CVEs: CVE-2026-69184, CVE-2020-22217, CVE-2022-4904, CVE-2026-69186

References:
  https://ubuntu.com/security/notices/USN-8951-1