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No exploitation reportedAwaiting NVD analysis

CVE-2026-123570

Hickory DNS from 0.18 before 0.26.2 Memory Amplification DoS via RR Counts

No exploitation reported by the sources we read.

  • Published2026-11-08
  • WeaknessCWE-400

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

The DNS wire-format message parser in hickory-proto (Hickory DNS) 0.18 before 0.26.2 preallocates record vectors sized by the untrusted ANCOUNT, NSCOUNT, and ARCOUNT header fields before reading record data. Remote attackers can send a UDP datagram, or a spoofed response to a client/resolver, with these counts set to 65535, forcing about 18MB of allocation per message.

Timeline

dates in UTC
  1. 2026-11-0801:38CVE publishedCNA

Versions per branch

Products declared by the CNA

As VulnCheck, the CNA that assigned this CVE, declared them in the CVE record; versions as written. NVD lists no product for this CVE yet: this is the only product data so far.

  • hickory-dnsother versions: not affected
    Affected
    • ≥ 0.18, < 0.26.2fixed in 0.26.2custom

    Not affected = 0.26.2

Source: the CNA record (CVE Program), © The MITRE Corporation,CVE Terms of UseCVE recordupdated 2026-11-08

Neither OSV.dev nor the vendor advisories we read list affected versions for CVE-2026-123570 yet.

Full record on NVD

Fix

No fix published by the sources we read yet. NVD record

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Metasploit modules
none listed
Metasploit Framework

Sources

  • CNACVSS 4.08.72026-11-08
  • CNACVSS 3.17.52026-11-08
  • NVDCVSS 3.17.5read 2026-11-08
  • CNAweakness (CWE)CWE-4002026-11-08
  • NVDweakness (CWE)CWE-400read 2026-11-08

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS 4.0 vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Published
2026-11-08
Last Modified
2026-11-08
NVD status
Received

Frequently asked questions

What is CVE-2026-123570?

The DNS wire-format message parser in hickory-proto (Hickory DNS) 0.18 before 0.26.2 preallocates record vectors sized by the untrusted ANCOUNT, NSCOUNT, and ARCOUNT header fields before reading record data. Remote attackers can send a UDP datagram, or a spoofed response to a client/resolver, with these counts set to 65535, forcing about 18MB of allocation per message.

Is CVE-2026-123570 actively exploited?

Active exploitation of CVE-2026-123570 has not been confirmed.

What is the CVSS score for CVE-2026-123570?

CVE-2026-123570 has a CVSS v3 base score of 7.5 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

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