CVE-2026-69184c-ares: CPU-exhaustion denial of service via unbounded DNS name compression pointer chains
Updated under an hour ago ()
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It affects c-ares. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
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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
- 7.5 HIGH (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Weakness (CWE)
- CWE-407
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- GitHub_M
- NVD analysis
- Awaiting Analysis
- Record last updated
- Sep 21, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
c-ares c-ares c_ares:c_ares (from the name) | before 1.34.7 | CNA record |
References
- https://github.com/c-ares/c-ares/security/advisories/GHSA-pjmc-gx33-gc76x-refsource-confirm
- https://github.com/c-ares/c-ares/pull/1164x-refsource-misc
- https://github.com/c-ares/c-ares/pull/1210x-refsource-misc
- https://github.com/c-ares/c-ares/commit/5c8341ba6ff3a8e4e4dfd616f8ed0418838b8b7bx-refsource-misc
- https://github.com/c-ares/c-ares/commit/f1288bbc70e9a1e0a77134c2382157e52d326aeax-refsource-misc
- https://github.com/c-ares/c-ares/releases/tag/v1.34.7x-refsource-misc
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.