CVE-2026-26018: CoreDNS Loop Detection Denial of Service Vulnerability

Vulnerability summary

CVE-2026-26018 is a high (CVSS 7.5) vulnerability in coredns. EPSS estimates a 1.24% chance of exploitation in the next 30 days, higher than 69.2% of scored vulnerabilities. 1 public exploit is recorded.

Timeline

1. 06-03-2026
   PublishedVulnerability first disclosed.
2. 15-07-2026
   Last modifiedVulnerability information updated.

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.

• CWE-337Predictable Seed in Pseudo-Random Number Generator (PRNG)A Pseudo-Random Number Generator (PRNG) is initialized from a predictable seed, such as the process ID or system time.
• CWE-400Uncontrolled Resource ConsumptionThe product does not properly control the allocation and maintenance of a limited resource.
• CWE-770Allocation of Resources Without Limits or ThrottlingThe product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated.
• CWE-1241Use of Predictable Algorithm in Random Number GeneratorThe device uses an algorithm that is predictable and generates a pseudo-random number.