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QSN-8951-1: c-ares vulnerabilities
October 21, 2026
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
| Release | Platform | Package | Exposure | Shipped version | Fixed version | Status |
|---|---|---|---|---|---|---|
| 6.9.1.001 | Ubuntu 22.04 LTS | libc-ares2 | Internally-facing | 1.18.1-1ubuntu0.22.04.4 | 1.18.1-1ubuntu0.22.04.4 | Fixed in this release |
| 6.9.0.464 | Ubuntu 22.04 LTS | libc-ares2 | Internally-facing | 1.18.1-1ubuntu0.22.04.3 | 1.18.1-1ubuntu0.22.04.4 | Fixed by QuantaStor security update |
| 6.8.6.015 | Ubuntu 22.04 LTS | libc-ares2 | Internally-facing | 1.18.1-1ubuntu0.22.04.3 | 1.18.1-1ubuntu0.22.04.4 | Fixed by QuantaStor security update |
| 6.8.5.018 | Ubuntu 22.04 LTS | libc-ares2 | Internally-facing | 1.18.1-1ubuntu0.22.04.3 | 1.18.1-1ubuntu0.22.04.4 | Fixed by QuantaStor security update |
| 6.8.4.038 | Ubuntu 22.04 LTS | libc-ares2 | Internally-facing | 1.18.1-1ubuntu0.22.04.3 | 1.18.1-1ubuntu0.22.04.4 | Fixed by QuantaStor security update |
| 6.8.3.018 | Ubuntu 22.04 LTS | libc-ares2 | Internally-facing | 1.18.1-1ubuntu0.22.04.3 | 1.18.1-1ubuntu0.22.04.4 | Fixed by QuantaStor security update |
| 6.8.2.002 | Ubuntu 22.04 LTS | libc-ares2 | Internally-facing | 1.18.1-1ubuntu0.22.04.3 | 1.18.1-1ubuntu0.22.04.4 | Fixed by QuantaStor security update |
| 6.8.1.007 | Ubuntu 22.04 LTS | libc-ares2 | Internally-facing | 1.18.1-1ubuntu0.22.04.3 | 1.18.1-1ubuntu0.22.04.4 | Fixed by QuantaStor security update |
| 6.8.0.205 | Ubuntu 22.04 LTS | libc-ares2 | Internally-facing | 1.18.1-1ubuntu0.22.04.3 | 1.18.1-1ubuntu0.22.04.4 | Fixed by QuantaStor security update |
Internally-facing: only accessible when logged into the QuantaStor console/ssh as the qadmin administrative sudo user; generally lower priority. Externally-facing: part of a service the storage platform presents on the network (or the kernel), so potentially reachable over the network.
CVEs
CVE-2026-69184, CVE-2020-22217, CVE-2022-4904, CVE-2026-69186
References
https://ubuntu.com/security/notices/USN-8951-1
https://nvd.nist.gov/vuln/detail/CVE-2026-69184
https://nvd.nist.gov/vuln/detail/CVE-2020-22217
https://nvd.nist.gov/vuln/detail/CVE-2022-4904
https://nvd.nist.gov/vuln/detail/CVE-2026-69186
Update
Fixes marked Fixed by QuantaStor security update are applied by upgrading QuantaStor with security patches included (Upgrade Manager). Fixed package versions:
| Platform | Package | Version |
|---|---|---|
| bionic | c-ares | 1.14.0-1ubuntu0.2+esm3 |
| Ubuntu 20.04 LTS | c-ares | 1.15.0-1ubuntu0.5+esm1 |
| Ubuntu 22.04 LTS | c-ares | 1.18.1-1ubuntu0.22.04.4 |
| Ubuntu 24.04 LTS | c-ares | 1.27.0-1.0ubuntu1.1 |
| resolute | c-ares | 1.34.6-1ubuntu0.2 |
| xenial | c-ares | 1.10.0-3ubuntu0.2+esm4 |