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Fencer Vulns
medium 5.4

CVE-2026-25500 json

Rack's Stored XSS in Rack::Directory via javascript: filenames rendered into anchor href

published 2026-02-17 8 mo ago modified 2026-09-10 1 mo ago also EUVD-2026-7916 , GHSA-whrj-4476-wvmp

cvss
5.4
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 19%
public exploits
0
none known

Summary

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.

Patch / fix

  • rubygems rack 2.2.22, 3.1.20, 3.2.5
  • rack rack 2.2.22, 3.1.20, 3.2.5
  • rack_project rack 2.2.22, 3.1.20, 3.2.5
  • ruby-rack Debian 12 2.2.22-0+deb12u1
  • ruby-rack Debian 13 3.1.20-0+deb13u1
  • ruby-rack Debian 14 3.2.5-1

debian advisories DEBIAN-CVE-2026-25500

  • ruby-rack Ubuntu 24.04 LTS 2.2.7-1ubuntu0.6
  • ruby-rack Ubuntu 25.10 3.1.16-0.1ubuntu0.2
  • ruby-rack Ubuntu 26.10, Ubuntu 26.04 LTS 3.2.4-1ubuntu1
  • ruby-rack Ubuntu Pro 20.04 LTS 2.0.7-2ubuntu0.1+esm9
  • ruby-rack Ubuntu Pro 22.04 LTS 2.1.4-5ubuntu1.2+esm2

ubuntu advisories UBUNTU-CVE-2026-25500

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • rubygem-rack-2.2 openSUSE Tumbleweed 2.2.22-1.1

opensuse advisories openSUSE-SU-2026:10286-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-25500 updated cvss 5.4

rubygem-rack: Rack stored XSS in Rack::Directory

  • Red Hat Logging Subsystem for Red Hat OpenShift openshift-logging/vector-rhel9, openshift-logging/fluentd-rhel9, openshift-logging/eventrouter-rhel9, openshift-logging/logging-view-plugin-rhel9, openshift-logging/cluster-logging-rhel9-operator, openshift-logging/log-file-metric-exporter-rhel9, +1 more Red Hat 3scale API Management Platform 2 3scale-amp21/zync, 3scale-amp22/zync, 3scale-amp24/zync, 3scale-amp25/zync, 3scale-amp26/zync, 3scale-amp20/system, +19 more Red Hat Enterprise Linux 7 pcs, pcs-snmp, python-clufter Red Hat Enterprise Linux 8 pcs, pcs-snmp Red Hat Enterprise Linux 9 pcs, pcs-snmp, ubi9/ruby-30, ubi9/ruby-33, rhel9/ruby-30, rhel9/ruby-33 Red Hat Enterprise Linux 10 pcs
    affected: workaround, no fix available “Fix deferred”
  • Red Hat Satellite 6 rubygem-rack
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
8 mo ago

Exploit prediction

0.27% chance of exploitation in the next 30 days, higher than 19% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/rack/rack/security/advisories/GHSA-whrj-4476-wvmp referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 5.4 CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
GitHub 3.1 5.4 CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

Affected packages

ecosystem package affected fixed in
rubygems rack
<2.2.22
>=3.0.0.beta1, <3.1.20
>=3.2.0, <3.2.5
2.2.22
3.1.20
3.2.5

Affected products

  • rack rack

Classification

Weakness
  • CWE-79 Improper Neutralization of Input During Web Page Generation

References

Sources

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.