CVE-2026-27480 json
Static Web Server: Timing-Based Username Enumeration in Basic Authentication
published 2026-02-20 8 mo ago modified 2026-06-17 4 mo ago also EUVD-2026-7717 , GHSA-qhp6-635j-x7r2
- cvss
- 5.3
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.4%
- EPSS 0.4% chance of exploitation in 30 days, percentile 33%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
- crates.io static-web-server 2.41.0
- static-web-server static_web_server 2.41.0
CISA SSVC
- Exploitation
- Proof of concept is public
- Automatable
- yes
- Technical impact
- partial
- Assessed
- 8 mo ago
Exploit prediction
0.39% chance of exploitation in the next 30 days, higher than 33% of all scored CVEs (FIRST EPSS, 2026-11-08).
Exploits and checks
- github.com https://github.com/static-web-server/static-web-server/security/advisories/GHSA-qhp6-635j-x7r2 referenced PoC, tagged "exploit" by a source, unverified
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 5.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N |
| GitHub | 3.1 | 5.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| crates.io | static-web-server | >=2.1.0, <2.41.0 |
2.41.0 |
Affected products
- static-web-server static-web-server
Classification
- Weakness
-
- CWE-204 Observable Response Discrepancy
References
-
github.com
/static-web-server/static-web-server/commit/7bf0fd425eb10dac9bf9ef5febce12c4dd039ce1
web, patch
-
github.com
/static-web-server/static-web-server/security/advisories/GHSA-qhp6-635j-x7r2
web, exploit, vendor-advisory
-
nvd.nist.gov
/vuln/detail/CVE-2026-27480
advisory
-
github.com
/static-web-server/static-web-server
package
Sources
- CVE List CVE-2026-27480
- GitHub Advisory GHSA-qhp6-635j-x7r2
- NVD CVE-2026-27480
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.
CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.