High severity · published Sep 18, 2026
CVE-2026-69184
c-ares: CPU-exhaustion denial of service via unbounded DNS name compression pointer chains
7.5
CVSS
0.5%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.5% · higher than 41% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
CA
c-ares · c-ares
< 1.34.7 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-69184
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-69184
github.com
https://github.com/c-ares/c-ares/commit/5c8341ba6ff3a8e4e4dfd616f8ed0418838b8b7b
github.com
https://github.com/c-ares/c-ares/commit/f1288bbc70e9a1e0a77134c2382157e52d326aea
github.com
https://github.com/c-ares/c-ares/pull/1164
github.com
https://github.com/c-ares/c-ares/pull/1210
github.com
https://github.com/c-ares/c-ares/releases/tag/v1.34.7
github.com
https://github.com/c-ares/c-ares/security/advisories/GHSA-pjmc-gx33-gc76
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