CVE-2026-27480
mediumPriorität · verfolgen · 0EPSS 0.004 · 33. PerzentilEUUSEPSS · bewertet 2026-10-27
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.
cvss
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Basiswert 0–10 · höher = schwerwiegender · Vektor überfahren zum Auflösen
SSVC
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schwächen
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betroffene Produkte (3)
Betroffene Produkte und Versionsbereiche.
- static-web-server static web server2.1.0 → 2.41.0nvdUScpe:2.3:a:static-web-server:static_web_server:*:*:*:*:*:*:*:*
Advisories (1)
Hersteller- und Ökosystem-Meldungen dazu.
- GHSA-qhp6-635j-x7r2Static Web Server affected by timing-based username enumeration in Basic Authentication due to early response on invalid usernames2026-02-20ghsa · osvUS
## Summary A 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. ## Details SWS validates the provided username before performing any password verification. - **Invalid Username:** The server returns a `401 Unauthorized` response immediately. - **Valid Username:** The server proceeds to verify the password (e.g., using `bcrypt`), which introduces a different execution path and measurable timing discrepancy. This allows an attacker to distinguish between existing and non-existing accounts by analyzing response times. ## PoC The following statistical results were obtained by measuring the mean response time over 100 iterations using a custom Rust script: | User Type | Average Response Time | | :--- | :--- | | **Invalid User** | 0.409861 ms | | **Valid User** | 0.250925 ms | | **Difference** | **~0.158936 ms** | While 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. ## Impact Users using the SWS' Basic Authentication feature are primarily impacted.
auch bekannt als (3)
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quellen
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Referenzen (7)
Externe Belege — Patches, Meldungen, Analysen.
- https://github.com/static-web-server/static-web-server/commit/7bf0fd425eb10dac9bf9ef5febce12c4dd039ce1cnnvd
- https://github.com/static-web-server/static-web-server/security/advisories/GHSA-qhp6-635j-x7r2cnnvd
- https://static-web-server.net/Patchcnnvd
- https://github.com/static-web-server/static-web-server/commit/7bf0fd425eb10dac9bf9ef5febce12c4dd039ce1enisa_euvd
- https://github.com/static-web-server/static-web-server/security/advisories/GHSA-qhp6-635j-x7r2enisa_euvd
- https://github.com/static-web-server/static-web-server/commit/7bf0fd425eb10dac9bf9ef5febce12c4dd039ce1Patchnvd
- https://github.com/static-web-server/static-web-server/security/advisories/GHSA-qhp6-635j-x7r2ExploitVendor Advisorynvd
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