CVE-2026-27480 – Static Web Server: Timing-Based Username Enumeration in Basic Authentication

CVE ID : CVE-2026-27480

Published : Feb. 21, 2026, 10:16 a.m. | 48 minutes ago

Description : Static Web Server (SWS) is a production-ready web server suitable for static web files or assets. In versions 2.1.0 through 2.40.1, a timing-based username enumeration vulnerability in Basic Authentication allows attackers to identify valid users by exploiting early responses for invalid usernames, enabling targeted brute-force or credential-stuffing attacks. SWS checks whether a username exists before verifying the password, causing valid usernames to follow a slower code path (e.g., bcrypt hashing) while invalid usernames receive an immediate 401 response. This timing discrepancy allows attackers to enumerate valid accounts by measuring response-time differences. This issue has been fixed in version 2.41.0.

Severity: 5.3 | MEDIUM

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