CVE-2026-69184
Publication date 18 September 2026
Last updated 21 October 2026
Ubuntu priority
Description
c-ares is an asynchronous resolver library. Prior to 1.34.7, ares_dns_name_parse() enforces backward DNS compression pointers but does not bound the total pointer hops or assembled name length. A malicious DNS server can send a response containing a long descending pointer chain and many resource records whose NAME or RDATA fields refer to the chain, causing repeated decompression work that grows quadratically with message size. A single crafted response can stall the single-threaded c-ares event loop and deny DNS resolution, without causing memory corruption or information disclosure. This issue is fixed in version 1.34.7.
Status
| Package | Ubuntu Release | Status |
|---|---|---|
| c-ares | 26.10 stonking |
Not affected
|
| 26.04 LTS resolute |
Fixed in 1.34.6-1ubuntu0.2
|
|
| 24.04 LTS noble |
Fixed in 1.27.0-1.0ubuntu1.1
|
|
| 22.04 LTS jammy |
Fixed in 1.18.1-1ubuntu0.22.04.4
|
|
| 20.04 LTS focal |
Fixed in 1.15.0-1ubuntu0.5+esm1
|
|
| 18.04 LTS bionic |
Fixed in 1.14.0-1ubuntu0.2+esm3
|
|
| 16.04 LTS xenial |
Fixed in 1.10.0-3ubuntu0.2+esm4
|
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CVSS version: CVSS v3.0
Base score
7.5 · High
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
References
Related Ubuntu Security Notices (USN)
- USN-8951-1
- c-ares vulnerabilities
- 21 October 2026