Is CVE-2026-34785 in the CISA KEV catalog?

No. CVE-2026-34785 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-34785?

CVE-2026-34785 has a CVSS v3 base score of 7.5 (HIGH).

What is the EPSS score for CVE-2026-34785?

CVE-2026-34785 has an EPSS score of 0.39% (31th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2026-34785?

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-2026-34785

HIGH

7.5

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::Static determines whether a request should be served as a static file using a simple string prefix check. When configured with URL prefixes such as "/css", it matches any request path that begins with that string, including unrelated paths such as "/css-config.env" or "/css-backup.sql". As a result, files under the static root whose names merely share the configured prefix may be served unintentionally, leading to information disclosure. This issue has been patched in versions 2.2.23, 3.1.21, and 3.2.6.

CWE-187 CWE-200Information Exposure CWE-552

How to fix

Remediation Available

ruby-rackDebian

Fixed in:3.2.6-2CVE-2026-34785

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

TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works

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

ConfidentialityHigh

IntegrityNone

AvailabilityNone

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

Exploit Intelligence

0.39%probability of exploitation in 30 days

31stpercentile

Low risk: more likely to be exploited than 31% of all known CVEs.

References

Vendor Advisory1

github.com

Other references3

Related Vulnerabilities

Other CWE-187 vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2024-41110	Critical	9.9	16%	-	Fix
CVE-2022-31802	Critical	9.8	1.2%	-	Fix
CVE-2024-39742	High	8.1	0.8%	-	Fix
CVE-2026-35031	Critical	9.9	0.8%	-	Fix
CVE-2026-44837	Medium	5.9	0.4%	-	Fix
CVE-2026-55602	High	8.6	0.3%	-	Fix

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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 2026-07-15.