CVE-2026-34230

HIGH EPSS 34.4%
Published Apr 2, 20262mo ago · Modified Jun 17, 20261w ago
7.5 CVSS 3.1
High
Find Similar
Published Apr 2, 2026 2mo ago
Last Modified Jun 17, 2026 1w ago

Description

Rack is a modular Ruby web server interface. Prior to versions 2.2.23, 3.1.21, and 3.2.6, Rack::Utils.select_best_encoding processes Accept-Encoding values with quadratic time complexity when the header contains many wildcard (*) entries. Because this method is used by Rack::Deflater to choose a response encoding, an unauthenticated attacker can send a single request with a crafted Accept-Encoding header and cause disproportionate CPU consumption on the compression middleware path. This results in a denial of service condition for applications using Rack::Deflater. This issue has been patched in versions 2.2.23, 3.1.21, and 3.2.6.

CVSS Details

Base Score
7.5
Exploitability
3.9
Impact
3.6
Vector string
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack Vector Network
Attack Complexity Low
Privileges Required None
User Interaction None
Scope Unchanged
Confidentiality None
Integrity None
Availability High

Threat Intelligence

EPSS Exploit Probability
34.4% percentile
Exploit & Patch Status
No Known Exploit
No Patch Available

Weaknesses 2

CWE-400 Uncontrolled Resource Consumption Resource Mgmt
CWE-407

Affected Products 3

VendorProductVersionRange
rackrack* <2.2.23
rackrack*≥3.0.0  –  <3.1.21
rackrack*≥3.2.0  –  <3.2.6

References 1

  • github.com https://github.com/rack/rack/security/advisories/GHSA-v569-hp3g-36wr
    Vendor Advisory

Remediation

No remediation data recorded yet

Check vendor advisories and the NVD entry for patch availability.