Rack up to 2.2.22/3.1.20/3.2.5 Request Path /css Rack::Static partial string comparison

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6.3	$0-$5k	0.00

Summaryinfo

A vulnerability classified as problematic has been found in Rack up to 2.2.22/3.1.20/3.2.5. This issue affects the function Rack::Static of the file /css of the component Request Path Handler. The manipulation leads to partial string comparison. This vulnerability is documented as CVE-2026-34785. The attack can be initiated remotely. There is not any exploit available. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability was found in Rack up to 2.2.22/3.1.20/3.2.5. It has been rated as problematic. This issue affects the function Rack::Static of the file /css of the component Request Path Handler. The manipulation with an unknown input leads to a partial string comparison vulnerability. Using CWE to declare the problem leads to CWE-187. The product performs a comparison that only examines a portion of a factor before determining whether there is a match, such as a substring, leading to resultant weaknesses. Impacted is confidentiality. The summary by CVE is:

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.

The advisory is shared at github.com. The identification of this vulnerability is CVE-2026-34785 since 03/30/2026. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. Technical details are known, but no exploit is available.

The vulnerability scanner Nessus provides a plugin with the ID 305959 (Ruby Rack < 2.2.23 / 3.0.x < 3.1.21 / 3.2 < 3.2.6 Multiple Vulnerabilities), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 2.2.23, 3.1.21 or 3.2.6 eliminates this vulnerability.

The vulnerability is also documented in the databases at Tenable (305959) and CERT Bund (WID-SEC-2026-1687). If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Affected

• IBM License Metric Tool

Productinfo

Name

• Rack

Version

• 2.2.0
• 2.2.1
• 2.2.2
• 2.2.3
• 2.2.4
• 2.2.5
• 2.2.6
• 2.2.7
• 2.2.8
• 2.2.9
• 2.2.10
• 2.2.11
• 2.2.12
• 2.2.13
• 2.2.14
• 2.2.15
• 2.2.16
• 2.2.17
• 2.2.18
• 2.2.19
• 2.2.20
• 2.2.21
• 2.2.22
• 3.1.0
• 3.1.1
• 3.1.2
• 3.1.3
• 3.1.4
• 3.1.5
• 3.1.6
• 3.1.7
• 3.1.8
• 3.1.9
• 3.1.10
• 3.1.11
• 3.1.12
• 3.1.13
• 3.1.14
• 3.1.15
• 3.1.16
• 3.1.17
• 3.1.18
• 3.1.19
• 3.1.20
• 3.2.0
• 3.2.1
• 3.2.2
• 3.2.3
• 3.2.4
• 3.2.5

Website

• Product: https://github.com/rack/rack/

CPE 2.3info

• 🔒
• 🔒
• 🔒

CPE 2.2info

• 🔒
• 🔒
• 🔒

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 6.4
VulDB Meta Temp Score: 6.3

VulDB Base Score: 5.3
VulDB Temp Score: 5.1
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 7.5
CNA Vector (GitHub_M): 🔒

CVSSv2info

AV	AC	Au	C	I	A
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳

Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock

VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Partial string comparison
CWE: CWE-187 / CWE-697
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Nessus ID: 305959
Nessus Name: Ruby Rack < 2.2.23 / 3.0.x < 3.1.21 / 3.2 < 3.2.6 Multiple Vulnerabilities

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Rack 2.2.23/3.1.21/3.2.6

Timelineinfo

03/30/2026 CVE reserved
04/02/2026 +3 days Advisory disclosed
04/02/2026 +0 days VulDB entry created
05/28/2026 +56 days VulDB entry last update

Sourcesinfo

Product: github.com

Advisory: GHSA-h2jq-g4cq-5ppq
Status: Confirmed

CVE: CVE-2026-34785 (🔒)
GCVE (CVE): GCVE-0-2026-34785
GCVE (VulDB): GCVE-100-354941
CERT Bund: WID-SEC-2026-1687 - IBM License Metric Tool: Mehrere Schwachstellen erm&ouml;glichen nicht spezifizierten Angriff

Entryinfo

Created: 04/02/2026 19:32
Updated: 05/28/2026 04:46
Changes: 04/02/2026 19:32 (65), 04/12/2026 01:24 (2), 05/28/2026 04:46 (7)
Complete: 🔍
Cache ID: 216::103

If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Discussion

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