Medium severity · published Apr 2, 2026
CVE-2026-34763
Rack: Rack::Directory info disclosure and DoS via unescaped regex interpolation
5.3
CVSS
0.2%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
Low
Integrity
None
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.2% · higher than 15% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
RA
rack · rack
< 2.2.23; >= 3.0.0.beta1, < 3.1.21; >= 3.2.0, < 3.2.6 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-34763
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-34763
Vendor Advisory
https://github.com/rack/rack/security/advisories/GHSA-7mqq-6cf9-v2qp
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