Is CVE-2026-34763 in the CISA KEV catalog?

No. CVE-2026-34763 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-34763?

CVE-2026-34763 has a CVSS v3 base score of 5.3 (MEDIUM).

What is the EPSS score for CVE-2026-34763?

CVE-2026-34763 has an EPSS score of 0.24% (15th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2026-34763?

Upgrade ruby-rack on debian unstable to 3.2.6-2 or later. Fixes are available for 5 affected products.

CVE & CISA-KEV Catalog

CVE-2026-34763

MEDIUM

5.3

CVSS v3

NVD

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.

CWE-625

How to fix

Remediation Available

ruby-rackDebian

Fixed in:3.2.6-2CVE-2026-34763

librack-rubyUbuntu

Fixed in:1.5.2-3+deb8u3ubuntu1~esm11USN-8182-1

librack-ruby1.8Ubuntu

Fixed in:1.5.2-3+deb8u3ubuntu1~esm11USN-8182-1

librack-ruby1.9.1Ubuntu

Fixed in:1.5.2-3+deb8u3ubuntu1~esm11USN-8182-1

ruby-rackUbuntu

Fixed in:1.5.2-3+deb8u3ubuntu1~esm11USN-8182-1

Fixed in:1.6.4-3ubuntu0.2+esm10USN-8182-1

Fixed in:1.6.4-4ubuntu0.2+esm10USN-8182-1

Fixed in:2.0.7-2ubuntu0.1+esm10USN-8182-1

Fixed in:2.1.4-5ubuntu1.2+esm3USN-8182-1

Fixed in:2.2.7-1ubuntu0.7USN-8182-1

Fixed in:3.1.16-0.1ubuntu0.3USN-8182-1

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityLow

IntegrityNone

AvailabilityNone

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

Exploit Intelligence

0.24%probability of exploitation in 30 days

15thpercentile

Low risk: more likely to be exploited than 15% of all known CVEs.

References

Vendor Advisory1

github.com

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-04-16.