CVE-2026-27145

MediumCVSS 6.5/10Last modified Sep 18, 2026

Description

(*x509.Certificate).VerifyHostname previously called matchHostnames in a loop over all DNS Subject Alternative Name (SAN) entries. This caused strings.Split(host, ".") to execute repeatedly on the same input hostname. With a large DNS SAN list, verification costs scaled quadratically based on the number of SAN entries multiplied by the hostname's label count. Because x509.Verify validates hostnames before building the certificate chain, this overhead occurred even for untrusted certificates.

Metrics

CVSS 3.1 6.5/10CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H

Weakness enumeration

CWE-606

Affected software

Source: the vendor's advisory (CNA). NVD analysis pending.

No affected versions have been published.

Timeline

Published: Jun 2, 2026
Last modified: Sep 18, 2026
NVD status: Awaiting Analysis

Related CVEs from 2026

CVE-2026-271464.5GetSimple CMS is a content management system. All versions of GetSimple CMS do not implement CSRF protection on the administrative file uplo CVE-2026-271475.4GetSimple CMS is a content management system. All versions of GetSimple CMS are vulnerable to XSS through SVG file uploads. Authenticated us CVE-2026-271489.6Storybook is a frontend workshop for building user interface components and pages in isolation. Prior to versions 7.6.23, 8.6.17, 9.1.19, an CVE-2026-271496.5Discourse is an open source discussion platform. Prior to versions 2025.12.2, 2026.1.1, and 2026.2.0, SQL injection in PM tag filtering (`li CVE-2026-271503.8Discourse is an open source discussion platform. Prior to versions 2025.12.2, 2026.1.1, and 2026.2.0, missing `validate_before_create` autho CVE-2026-271512.7Discourse is an open source discussion platform. Prior to versions 2025.12.2, 2026.1.1, and 2026.2.0, the `move_posts` action only checked `CVE-2026-271523.8Discourse is an open source discussion platform. Prior to versions 2025.12.2, 2026.1.1, and 2026.2.0, DM communication-preference bypass whe CVE-2026-271532.7Discourse is an open source discussion platform. Prior to versions 2025.12.2, 2026.1.1, and 2026.2.0, moderators could export user Chat DMs CVE-2026-271546.1Discourse is an open source discussion platform. Prior to versions 2025.12.2, 2026.1.1, and 2026.2.0, a user full name can be evaluated as r CVE-2026-271566.1NiceGUI is a Python-based UI framework. Prior to version 3.8.0, several NiceGUI APIs that execute methods on client-side elements (`Element.CVE-2026-27164.4The Client Testimonial Slider plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'Testimonial Heading' setting in all CVE-2026-271617.5GetSimple CMS is a content management system. All versions of GetSimple CMS rely on .htaccess files to restrict access to sensitive director