CoreDNS Loop-Detection Plugin DoS via Predictable PRNG <1.14.2
CVE-2026-26018 Published on March 6, 2026
CoreDNS Loop Detection Denial of Service Vulnerability
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.
Vulnerability Analysis
CVE-2026-26018 is exploitable with network access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity, and a high impact on availability.
Weakness Types
What is a PRNG Vulnerability?
A Pseudo-Random Number Generator (PRNG) is initialized from a predictable seed, such as the process ID or system time. The use of predictable seeds significantly reduces the number of possible seeds that an attacker would need to test in order to predict which random numbers will be generated by the PRNG.
CVE-2026-26018 has been classified to as a PRNG vulnerability or weakness.
Allocation of Resources Without Limits or Throttling
The software allocates a reusable resource or group of resources on behalf of an actor without imposing any restrictions on the size or number of resources that can be allocated, in violation of the intended security policy for that actor.
What is a Resource Exhaustion Vulnerability?
The software does not properly control the allocation and maintenance of a limited resource, thereby enabling an actor to influence the amount of resources consumed, eventually leading to the exhaustion of available resources.
CVE-2026-26018 has been classified to as a Resource Exhaustion vulnerability or weakness.
Use of Predictable Algorithm in Random Number Generator
The device uses an algorithm that is predictable and generates a pseudo-random number.
Products Associated with CVE-2026-26018
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Affected Versions
coredns:- Version < 1.14.2 is affected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.