https://vulnerability.circl.lu Contains only the most 10 recent entries. http://www.rssboard.org/rss-specification python-feedgen en Tue, 29 Sep 2026 23:45:41 +0000 https://vulnerability.circl.lu/vuln/cve-2026-34230 <p><strong>Affected:</strong> rack</p> <p>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.</p> <p><strong>Affected:</strong> rack</p> <p>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.</p> https://vulnerability.circl.lu/vuln/cve-2026-34230 https://vulnerability.circl.lu/vuln/ghsa-v569-hp3g-36wr <p><strong>Affected:</strong> RubyGems: rack</p> <p>## Summary</p> <p>`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.</p> <p>This results in a denial of service condition for applications using `Rack::Deflater`.</p> <p>## Details</p> <p>`Rack::Utils.select_best_encoding` expands parsed `Accept-Encoding` values into a list of candidate encodings. When an entry is `*`, the method computes the set of concrete encodings by subtracting the encodings already present in the request:</p> <p>```ruby if m == &#34;*&#34; (available_encodings - accept_encoding.map(&amp;:first)).each do |m2| expanded_accept_encoding &lt;&lt; [m2, q, preference] end else expanded_accept_encoding &lt;&lt; [m, q, preference] end ```</p> <p>Because `accept_encoding.map(&amp;:first)` is evaluated inside the loop, it is recomputed for each wildcard entry. If the request contains `N` wildcard entries, this produces repeated scans over the full parsed header and causes quadratic behavior.</p> <p>After expansion, the method also performs additional work over `expanded_accept_encoding`, including per-entry deletion, which further increases the cost for large inputs.</p> <p>`Rack::Deflater` invokes this method for each request when the middleware is enabled:</p> <p>```ruby Utils.selec…</p> <p><strong>Affected:</strong> RubyGems: rack</p> <p>## Summary</p> <p>`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.</p> <p>This results in a denial of service condition for applications using `Rack::Deflater`.</p> <p>## Details</p> <p>`Rack::Utils.select_best_encoding` expands parsed `Accept-Encoding` values into a list of candidate encodings. When an entry is `*`, the method computes the set of concrete encodings by subtracting the encodings already present in the request:</p> <p>```ruby if m == &#34;*&#34; (available_encodings - accept_encoding.map(&amp;:first)).each do |m2| expanded_accept_encoding &lt;&lt; [m2, q, preference] end else expanded_accept_encoding &lt;&lt; [m, q, preference] end ```</p> <p>Because `accept_encoding.map(&amp;:first)` is evaluated inside the loop, it is recomputed for each wildcard entry. If the request contains `N` wildcard entries, this produces repeated scans over the full parsed header and causes quadratic behavior.</p> <p>After expansion, the method also performs additional work over `expanded_accept_encoding`, including per-entry deletion, which further increases the cost for large inputs.</p> <p>`Rack::Deflater` invokes this method for each request when the middleware is enabled:</p> <p>```ruby Utils.selec…</p> https://vulnerability.circl.lu/vuln/ghsa-v569-hp3g-36wr