Vulnerability · CVE-2026-34763
Rack is a modular Ruby web server interface.
Published Apr 2, 2026 · catalog updated Jul 24, 2026 · Rack is a modular
Check if you run it
No confirmed exploitation is on record for CVE-2026-34763. EPSS is 0.33%. Act only if a listed version of Rack is a modular is installed.
Gaps on this record
- The stored product name is a package slug. The name on this page is taken from the title (Rack is a modular).
- No version range is stored. A customer cannot check an installed version against this record.
- No vendor fix or required action is stored. Compare the linked advisory before you change production.
- Severity
- Medium5.3
- Known exploitation
- Not in CISA/VulnCheck KEV
- EPSS
- 0.33%
- Remediation
- Advisory link
- Affected products
- cpe rack/rack
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.
Are you affected?
Enter the version you run. The result uses only the ranges stored on this record.
The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.
- cpe rack/rackversion unspecified
How to fix CVE-2026-34763
Recommended remediation
A patch or advisory reference is linked. Open the original publisher for availability by product version.
Official advisories
What to do
Three questions, each answered from this record only. Confirm the vendor advisory before you patch.
Should you patch?
No confirmed exploitation is on record for CVE-2026-34763. EPSS is 0.33%. Act only if a listed version of Rack is a modular is installed.
Which versions are affected?
Affected version ranges are not on this record. Compare the installed version with the linked vendor advisory before you change production.
What should an analyst verify?
CWE-625. EPSS 0.33%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.
Code
The project this record applies to. Exploit listings stay in References.
Timeline
Detection, updates, and resolution for this record.
Apr 2, 2026 · NIST NVD
Detected
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 outpu
Jul 24, 2026 · NIST NVD
Updated
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 outpu
Sources
- CVE.orgVulnerability recordCVE-2026-34763
Official CVE identifier
cve.org - FIRST EPSSExploitation probabilityCVE-2026-34763
30-day exploitation probability 0.3%
first.org - NIST NVDVulnerability recordCVE-2026-34763
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 .,
nvd.nist.gov
References
Freshness
Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.