Vulnerability · Published Apr 2, 2026 · Assigned by GitHub_M
CVE-2026-34763Rack: Rack::Directory info disclosure and DoS via unescaped regex interpolation
Medium 5.3
In plain English
A medium-severity security flaw in rack from rack. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 16% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | ruby-rack | 2.2.22-0+deb12u2 | DEBIAN-CVE-2026-34763 |
| Debian:13 | ruby-rack | 3.1.20-0+deb13u2 | DEBIAN-CVE-2026-34763 |
| Debian:14 | ruby-rack | 3.2.6-2 | DEBIAN-CVE-2026-34763 |
| RubyGems | rack | 2.2.23 | GHSA-7mqq-6cf9-v2qp |
| RubyGems | rack | 3.1.21 | GHSA-7mqq-6cf9-v2qp |
| RubyGems | rack | 3.2.6 | GHSA-7mqq-6cf9-v2qp |
| Ubuntu:24.04:LTS | ruby-rack | 2.2.7-1ubuntu0.7 | UBUNTU-CVE-2026-34763 |
| Ubuntu:25.10 | ruby-rack | 3.1.16-0.1ubuntu0.3 | UBUNTU-CVE-2026-34763 |
| Ubuntu:26.04:LTS | ruby-rack | 3.2.4-1ubuntu1.1 | UBUNTU-CVE-2026-34763 |
| Ubuntu:26.04:LTS | ruby-rack | 3.2.4-1ubuntu1.1 | USN-8989-1 |
Affected products (as reported)
Weakness: CWE-625 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
References
- https://github.com/rack/rack/security/advisories/GHSA-7mqq-6cf9-v2qp x_refsource_CONFIRM