CVE-2026-25500
Stored XSS in Rack::Directory via javascript: filenames rendered into anchor href
Description
Rack is a modular Ruby web server interface. Prior to versions 2.2.22, 3.1.20, and 3.2.5, `Rack::Directory` generates an HTML directory index where each file entry is rendered as a clickable link. If a file exists on disk whose basename starts with the `javascript:` scheme (e.g. `javascript:alert(1)`), the generated index contains an anchor whose `href` is exactly `javascript:alert(1)`. Clicking the entry executes JavaScript in the browser (demonstrated with `alert(1)`). Versions 2.2.22, 3.1.20, and 3.2.5 fix the issue.
How to fix CVE-2026-25500
To remediate CVE-2026-25500, upgrade the affected package to a fixed version below.
- —upgrade to 2.1.4-3+deb11u5 or later
- —upgrade to 2.2.22 or later
Is CVE-2026-25500 being exploited?
Low — EPSS is 0.0%, meaning exploitation activity has not been observed at scale.
Affected packages (2)
- from 0, < 2.1.4-3+deb11u5
- from 0, < 2.2.22
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | MEDIUM5.4 | CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N |