{"id":"GHSA-qhp6-635j-x7r2","summary":"Static Web Server affected by timing-based username enumeration in Basic Authentication due to early response on invalid usernames","details":"## Summary\n\nA Timing-based username enumeration in Basic Authentication vulnerability due to early response on invalid usernames could allow attackers to identify valid users and focus their efforts on targeted brute-force or credential-stuffing attacks.\n\n## Details\n\nSWS validates the provided username before performing any password verification.\n- **Invalid Username:** The server returns a `401 Unauthorized` response immediately.\n- **Valid Username:** The server proceeds to verify the password (e.g., using `bcrypt`), which introduces a different execution path and measurable timing discrepancy.\n\nThis allows an attacker to distinguish between existing and non-existing accounts by analyzing response times.\n\n## PoC\n\nThe following statistical results were obtained by measuring the mean response time over 100 iterations using a custom Rust script:\n\n| User Type | Average Response Time |\n| :--- | :--- |\n| **Invalid User** | 0.409861 ms |\n| **Valid User** | 0.250925 ms |\n| **Difference** | **~0.158936 ms** |\n\nWhile the valid user responded faster in this specific test environment, the statistically significant gap confirms that the authentication logic does not execute in constant time.\n\n## Impact\n\nUsers using the SWS' Basic Authentication feature are primarily impacted.","aliases":["CVE-2026-27480"],"modified":"2026-02-23T22:58:12.472017Z","published":"2026-02-20T18:25:27Z","database_specific":{"github_reviewed_at":"2026-02-20T18:25:27Z","nvd_published_at":"2026-02-21T10:16:12Z","cwe_ids":["CWE-204"],"severity":"MODERATE","github_reviewed":true},"references":[{"type":"WEB","url":"https://github.com/static-web-server/static-web-server/security/advisories/GHSA-qhp6-635j-x7r2"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-27480"},{"type":"WEB","url":"https://github.com/static-web-server/static-web-server/commit/7bf0fd425eb10dac9bf9ef5febce12c4dd039ce1"},{"type":"PACKAGE","url":"https://github.com/static-web-server/static-web-server"}],"affected":[{"package":{"name":"static-web-server","ecosystem":"crates.io","purl":"pkg:cargo/static-web-server"},"ranges":[{"type":"SEMVER","events":[{"introduced":"2.1.0"},{"fixed":"2.41.0"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/02/GHSA-qhp6-635j-x7r2/GHSA-qhp6-635j-x7r2.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N"}]}