CVE-2026-22860 is a high-severity (CVSS 7.5) Path Traversal vulnerability in rack. A fix is available for rack — see the affected versions and patch details below.
Rack has a Directory Traversal via Rack:Directory
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-22860.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
rack💎rack💎rackReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects RubyGems packages — download data is not available via public APIs for these ecosystems.
Description
Summary
Rack::Directory’s path check used a string prefix match on the expanded path. A request like /../root_example/ can escape the configured root if the target path starts with the root string, allowing directory listing outside the intended root.
Details
In directory.rb, File.expand_path(File.join(root, path_info)).start_with?(root) does not enforce a path boundary. If the server root is /var/www/root, a path like /var/www/root_backup passes the check because it shares the same prefix, so Rack::Directory will list that directory also.
Impact
Information disclosure via directory listing outside the configured root when Rack::Directory is exposed to untrusted clients and a directory shares the root prefix (e.g., public2, www_backup).
Mitigation
- Update to a patched version of Rack that correctly checks the root prefix.
- Don't name directories with the same prefix as one which is exposed via
Rack::Directory.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 💎RubyGems | rack | all versions | 2.2.22bundle update rack --conservative |
| 💎RubyGems | rack | ≥ 3.0.0.beta1&&< 3.1.20 | 3.1.20bundle update rack --conservative |
| 💎RubyGems | rack | ≥ 3.2.0&&< 3.2.5 | 3.2.5bundle update rack --conservative |
Affected Products
rackrackDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for rack, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update rack to 2.2.22 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-22860 is resolved across your whole dependency graph.
Workarounds
Resolve every user-supplied path to its canonical form and reject anything that escapes the intended directory, and run the component under an account that has no read or write access outside the directory it legitimately serves.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.Source: Red Hat security advisory for CVE-2026-22860 (CC BY 4.0)
Frequently Asked Questions
Is CVE-2026-22860 in your dependencies?
Find it across RubyGems, including transitive dependencies.