Vulnerability in C-Ares
CVE-2026-69184
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.
Published · last modified .
CVSS v3 metric
CVSS v3 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.
EPSS exploit prediction
EPSS: 0.005 (41.3th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 41st percentile — 41.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.007 · newest: 0.005 · change: -0.002
Affected products
- C-Ares — versions < 1.34.7
Weakness classification (CWE)
References
- github.com/c-ares/c-ares/security/advisories/GHSA-pjmc-gx33-gc76
- github.com/c-ares/c-ares/pull/1164
- github.com/c-ares/c-ares/pull/1210
- github.com/c-ares/c-ares/commit/5c8341ba6ff3a8e4e4dfd616f8ed0418838b8b7b
- github.com/c-ares/c-ares/commit/f1288bbc70e9a1e0a77134c2382157e52d326aea
- github.com/c-ares/c-ares/releases/tag/v1.34.7
Frequently asked questions
- What is CVE-2026-69184?
- CVE-2026-69184 is a high-severity vulnerability in C-Ares, classified under Inefficient Algorithmic Complexity. CVSS score: 7.5/10. Published 2026-09-18.
- How severe is CVE-2026-69184?
- High severity. CVSS v3 base score is 7.5 out of 10.