Rack: Rack::Directory info disclosure and DoS via unescaped regex interpolation
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- Low · None · None
- Fix status
- Partial Red Hat: 6 without a fix
Attack profile from CVSS 3.1 · CNA. Fix status from CNA, GitHub and Red Hat.
Summary
Rack is a modular Ruby web server interface. Prior to versions 2.2.23, 3.1.21, and 3.2.6, Rack::Directory interpolates the configured root path directly into a regular expression when deriving the displayed directory path. If root contains regex metacharacters such as +, *, or ., the prefix stripping can fail and the generated directory listing may expose the full filesystem path in the HTML output. This issue has been patched in versions 2.2.23, 3.1.21, and 3.2.6.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- Yes
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| rack | rack | before 2.2.23; 3.0.0.beta1 to before 3.1.21; 3.2.0 to before 3.2.6 | 2.2.23, 3.1.21, 3.2.6 | Patch available | CNA |
| — | rack (RubyGems) | before 2.2.23 | 2.2.23 | Patch available | GHSA-7mqq-6cf9-v2qp |
| — | rack (RubyGems) | 3.0.0.beta1 to before 3.1.21 | 3.1.21 | Patch available | GHSA-7mqq-6cf9-v2qp |
| — | rack (RubyGems) | 3.2.0 to before 3.2.6 | 3.2.6 | Patch available | GHSA-7mqq-6cf9-v2qp |
- rack Vendorrack Affected before 2.2.23; 3.0.0.beta1 to before 3.1.21; 3.2.0 to before 3.2.6 Fixed in 2.2.23, 3.1.21, 3.2.6 Patch available CNA
- rack (RubyGems) Vendor— Affected before 2.2.23 Fixed in 2.2.23 Patch available GHSA-7mqq-6cf9-v2qp
- rack (RubyGems) Vendor— Affected 3.0.0.beta1 to before 3.1.21 Fixed in 3.1.21 Patch available GHSA-7mqq-6cf9-v2qp
- rack (RubyGems) Vendor— Affected 3.2.0 to before 3.2.6 Fixed in 3.2.6 Patch available GHSA-7mqq-6cf9-v2qp
Remediation
- Fix · CNA rack (rack) Fixed in 2.2.23, 3.1.21, 3.2.6
- Fix · GHSA-7mqq-6cf9-v2qp rack (RubyGems) Fixed in 2.2.23 Advisory →
- Fix · GHSA-7mqq-6cf9-v2qp rack (RubyGems) Fixed in 3.1.21 Advisory →
- Fix · GHSA-7mqq-6cf9-v2qp rack (RubyGems) Fixed in 3.2.6 Advisory →
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Logging Subsystem for Red Hat OpenShift | Affected | No fix yet: Fix deferred |
| Red Hat 3scale API Management Platform 2 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 10 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 7 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 8 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 9 | Affected | No fix yet: Fix deferred |
Timeline
- 2026-10-02 Threatist record created from CVE-2026-34763
- 2026-10-03 Alias added: GHSA-7mqq-6cf9-v2qp
References
More Rack vulnerabilities
- TI-2024-16580 Rack ReDos in content type parsing (2nd degree polynomial) CVSS 3.1HIGH 7.5
- TI-2024-17236 Possible Denial of Service Vulnerability in Rack Header Parsing CVSS 3.1HIGH 7.5
- TI-2024-17231 Possible DoS Vulnerability with Range Header in Rack CVSS 3.1HIGH 7.5
- TI-2023-12254 Uncontrolled resource consumption in https://github.com/rack/rack CVSS 3.1HIGH 7.5
- TI-2025-38165 Rack's multipart parser buffers unbounded per-part headers, enabling DoS (memory exhaustion) CVSS 3.1HIGH 7.5
- TI-2025-38163 Rack's unbounded multipart preamble buffering enables DoS (memory exhaustion) CVSS 3.1HIGH 7.5
Sources
- CVE-2026-34763 · CVE Program
- CVE-2026-34763 · NVD
- FIRST EPSS
- GHSA-7mqq-6cf9-v2qp · GitHub Advisory Database · CC BY 4.0
- CVE-2026-34763 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences