CVE-2026-34230

A flaw was found in Rack. An unauthenticated attacker can exploit a vulnerability in the Rack::Utils.select_best_encoding method by sending a specially crafted Accept-Encoding header with numerous wildcard entries. This leads to quadratic time complexity during processing, causing disproportionate CPU consumption. Consequently, this can result in a Denial of Service (DoS) condition for applications utilizing Rack::Deflater.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.