CVE-2026-26017Network attack vector

DNS access-control bypass via post-check rewriting

Published Mar 6, 2026 · Updated Mar 6, 2026

Access-control bypass in CoreDNS before 1.14.2 allows remote authenticated users to discover restricted internal DNS records. The default plugin.cfg evaluates acl and policy plugins against the original query name, then rewrite changes that approved name to a restricted domain before backend resolution. Exploitation requires both access-control and rewrite rules; successful queries disclose internal service names and addresses without changing DNS data.

CVSS severity7.7
High
EPSS probability0.39%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Access-control bypass in CoreDNS before 1.14.2 allows remote authenticated users to discover restricted internal DNS records. The default plugin.cfg evaluates acl and policy plugins against the original query name, then rewrite changes that approved name to a restricted domain before backend resolution. Exploitation requires both access-control and rewrite rules; successful queries disclose internal service names and addresses without changing DNS data.

The record

CVE
CVE-2026-26017
Published
Mar 6, 2026
Updated
Mar 6, 2026
Vendor
CoreDNS
Product
CoreDNS
Classifications
CWE-367, T1018
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 6, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 6, 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=< 1.14.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

CoreDNS · CoreDNSversion=< 1.14.2

Published CVSS scores

7.7redhat-SADPCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N
6.3NIST NVDCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:N/A:N
7.7GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N

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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-367Time-of-check Time-of-use (TOCTOU) Race Condition
T1018Remote System Discovery

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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