CVE-2026-40210Network attack vector

Memory disclosure or crash via MAC over-read

Published Jun 25, 2026 · Updated Jun 25, 2026

Buffer over-read in PowerDNS DNSdist 1.9.0 through 1.9.14 and 2.0.0 through 2.0.6 allows remote attackers to read memory or crash. SetMacAddrAction passes a six-byte MAC array to generateEDNSOption as an unterminated character pointer, so string construction reads beyond the array. The flaw is reachable only when SetMacAddrAction is configured; crafted DNS queries can expose adjacent process bytes in forwarded EDNS data or terminate dnsdist.

CVSS severity4.8
Medium
EPSS probability0.26%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Buffer over-read in PowerDNS DNSdist 1.9.0 through 1.9.14 and 2.0.0 through 2.0.6 allows remote attackers to read memory or crash. SetMacAddrAction passes a six-byte MAC array to generateEDNSOption as an unterminated character pointer, so string construction reads beyond the array. The flaw is reachable only when SetMacAddrAction is configured; crafted DNS queries can expose adjacent process bytes in forwarded EDNS data or terminate dnsdist.

The record

CVE
CVE-2026-40210
Published
Jun 25, 2026
Updated
Jun 25, 2026
Vendor
PowerDNS
Product
DNSdist
Classifications
CWE-126, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 25, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 25, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=1.9.0 <1.9.15
  2. Affected versionversion=2.0.0 <2.0.7

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

PowerDNS · DNSdistversion=1.9.0 <1.9.15; version=2.0.0 <2.0.7

Published CVSS scores

4.8Open-XchangeCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:L

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-126Buffer Over-read
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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