CVE-2026-25500 | Rack's Stored XSS in Rack::Directory via javascript: filenames rendered into anchor href

Exp

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.

Published: 2026-02-18 Last update: 2026-06-17 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-25500 is rated Exploit Available (50/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.22%). 1 public exploit reference(s) are indexed (Exploit-DB). Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2026-25500

EDB-ID Source Kind Published Link
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2026-25500

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.03% 0.22% +0.19%
2 2026-02-19 — 0.03% —

Full EPSS history (2 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-25500

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.4 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N)
Service keeps running; no real outage angle.
 2.3 2.7 [email protected]

Weakness enumeration for CVE-2026-25500

GitHub Security Advisory for CVE-2026-25500

GHSA-whrj-4476-wvmp · Severity: medium · Ecosystem: rubygems — Stored XSS in Rack::Directory via javascript: filenames rendered into anchor href

OS Trackers for CVE-2026-25500

vendor priority summary link
debian not yet assigned CVE-2026-25500 not yet assigned priority: Debian including 1 source packages (ruby-rack), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2026-25500
redhat medium — https://access.redhat.com/security/cve/CVE-2026-25500
suse medium — https://www.suse.com/security/cve/CVE-2026-25500/
ubuntu medium CVE-2026-25500 medium priority: Ubuntu including 1 source packages (ruby-rack), 8 status rows across 8 suites (bionic, focal, jammy, noble, questing, trusty, upstream, xenial): released 5, ignored 3. https://ubuntu.com/security/CVE-2026-25500

Affected software / configurations for CVE-2026-25500

Vendor Product Version Raw CPE
rack rack < 2.2.22 cpe:2.3:a:rack:rack:*:*:*:*:*:ruby:*:*
rack rack >= 3.0.0, < 3.1.20 cpe:2.3:a:rack:rack:*:*:*:*:*:ruby:*:*
rack rack >= 3.2.0, < 3.2.5 cpe:2.3:a:rack:rack:*:*:*:*:*:ruby:*:*

References for CVE-2026-25500

cvelogic Threat Intelligence