CVE-2026-69184 — c-ares: CPU-exhaustion denial of service via unbounded DNS name compression pointer chains
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 assemb…
Published: 2026-09-18 · CVSS: 7.5 · CVSS 3.1
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.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7