CVE-2026-27480
MEDIUMDescription
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.
How to fix
TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works
Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.
CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
Exploit Intelligence
Low risk: more likely to be exploited than 28% of all known CVEs.
References
Related Vulnerabilities
Other CWE-204 vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2022-41697 | Medium | 5.3 | 20% | - | - |
| CVE-2016-9499 | Medium | 5.3 | 7.8% | - | Fix |
| CVE-2019-19030 | Medium | 5.3 | 1.9% | - | Fix |
| CVE-2022-0564 | Medium | 5.3 | 1.4% | - | Fix |
| CVE-2021-20049 | High | 7.5 | 1.3% | - | Fix |
| CVE-2021-39189 | Medium | 5.3 | 1.3% | - | Fix |
Common questions
How do I fix CVE-2026-27480?
Upgrade static web server to 2.41.0 or later.
Is CVE-2026-27480 being actively exploited?
Not that we know of. CVE-2026-27480 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.35% is the estimated probability that it will be exploited in the next 30 days. That is higher than 28% of all scored CVEs.
How severe is CVE-2026-27480?
CVE-2026-27480 has a CVSS v3 base score of 5.3, rated medium. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
What does CVE-2026-27480 affect?
Published advisories record a fix for static web server (NVD). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.
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Markdown
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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-02-24.