CVE-2025-58187 is a vulnerability identified in the Go programming language's standard library, specifically within the crypto/x509 package responsible for certificate validation. The root cause is an inefficient algorithmic design in the name constraint checking algorithm, which causes the processing time to scale non-linearly with the size of the certificate chain input. This inefficiency can be exploited by an attacker to craft specially designed certificate chains that cause excessive CPU consumption during validation, leading to denial-of-service (DoS) conditions. The vulnerability affects all Go versions from the initial release up to version 1.25.0. The CVSS v3.1 base score is 7.5, reflecting a high severity primarily due to the impact on availability (A:H), with no impact on confidentiality or integrity. The attack vector is network-based (AV:N), requires no privileges (PR:N), and no user interaction (UI:N). The scope remains unchanged (S:U). No known exploits have been reported in the wild as of the publication date. The vulnerability is classified under CWE-407 (Improper Control of Resource Consumption). Since Go is widely used in backend services, cloud infrastructure, and security-sensitive applications, this vulnerability poses a risk to any system performing certificate validation using the affected library. The lack of a patch at the time of reporting necessitates interim mitigations to reduce exposure.

The primary impact of CVE-2025-58187 is on the availability of services that use the Go crypto/x509 package for certificate validation. An attacker can exploit the inefficient algorithm to cause excessive CPU usage, potentially leading to denial-of-service conditions. For European organizations, this could disrupt critical services such as web servers, API gateways, and internal microservices that rely on Go for TLS certificate validation. Industries with high reliance on secure communications, such as finance, healthcare, and government, may experience service outages or degraded performance. Additionally, cloud service providers and SaaS companies using Go could face scalability and reliability issues. The vulnerability does not affect confidentiality or integrity directly but can indirectly impact business operations and trust due to service unavailability. The absence of required authentication or user interaction lowers the barrier for exploitation, increasing the risk profile. Organizations with automated certificate validation pipelines are particularly vulnerable to large-scale or targeted DoS attacks leveraging this flaw.

1. Upgrade to a patched version of the Go standard library once it becomes available, as this is the definitive fix for the vulnerability. 2. Until a patch is released, implement input validation and size limits on certificate chains to prevent processing of excessively large or complex certificates. 3. Employ rate limiting and resource usage monitoring on services performing certificate validation to detect and mitigate abnormal CPU consumption patterns. 4. Consider isolating certificate validation processes in separate containers or sandboxes with strict resource quotas to contain potential DoS impacts. 5. Review and harden TLS termination points and certificate validation logic to reject suspicious or non-standard certificates early. 6. Monitor security advisories from the Go project and related ecosystem tools for updates and patches. 7. Conduct internal audits of all services using Go's crypto/x509 package to identify exposure and prioritize remediation efforts. 8. Educate development and operations teams about the vulnerability and encourage proactive incident response planning.