CVE-2026-26018

CoreDNS Loop Detection Denial of Service Vulnerability

State: Published
Severity: 7.5 High
Published: Mar 6, 2026
Updated: Jul 15, 2026
Reserved: Feb 9, 2026

Description

CoreDNS is a DNS server that chains plugins. Prior to version 1.14.2, a denial of service vulnerability exists in CoreDNS's loop detection plugin that allows an attacker to crash the DNS server by sending specially crafted DNS queries. The vulnerability stems from the use of a predictable pseudo-random number generator (PRNG) for generating a secret query name, combined with a fatal error handler that terminates the entire process. This issue has been patched in version 1.14.2.

Scores

CVSS	Score	Vector	Source
3.1	7.5 High	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H	GitHub_M
3.1	7.5 High	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H	redhat-SADP

Weaknesses

CWE-337 Predictable Seed in Pseudo-Random Number Generator (PRNG)
CWE-770 Allocation of Resources Without Limits or Throttling
CWE-400 Uncontrolled Resource Consumption
CWE-1241 Use of Predictable Algorithm in Random Number Generator

Affected Products

Product	Versions
corednscoredns	< 1.14.2Affected

References

https://github.com/coredns/coredns/security/advisories/GHSA-h75p-j8xm-m278
https://github.com/coredns/coredns/releases/tag/v1.14.2
https://access.redhat.com/security/cve/CVE-2026-26018vdb-entry
RHBZ#2445242issue-tracking
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-26018.json
https://access.redhat.com/errata/RHSA-2026:36873vendor-advisory
https://access.redhat.com/errata/RHSA-2026:25127vendor-advisory
https://access.redhat.com/errata/RHSA-2026:8151vendor-advisory

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