diff --git a/benchmarks/lobsters/Gemfile b/benchmarks/lobsters/Gemfile
index 66d8669c..7c51ad85 100644
--- a/benchmarks/lobsters/Gemfile
+++ b/benchmarks/lobsters/Gemfile
@@ -45,7 +45,7 @@ gem "rqrcode_core", github: "whomwah/rqrcode_core"
 gem "pdf-reader"
 gem "nokogiri", ">= 1.13.9"
 gem "htmlentities"
-gem "commonmarker", ">= 0.23.6", "< 1.0" # The v1.0 Rust gem doesn't compile on Ruby master
+gem "commonmarker", github: "ianks/commonmarker", branch: "hotfix/ruby-4-1"
 
 # perf - skip for benchmarking
 group :development do
diff --git a/benchmarks/lobsters/Gemfile.lock b/benchmarks/lobsters/Gemfile.lock
index 9a4d094b..fe961086 100644
--- a/benchmarks/lobsters/Gemfile.lock
+++ b/benchmarks/lobsters/Gemfile.lock
@@ -1,3 +1,11 @@
+GIT
+  remote: https://github.com/ianks/commonmarker.git
+  revision: 6ea4f5a2be0423206dbaeca7108035a70a149ab7
+  branch: hotfix/ruby-4-1
+  specs:
+    commonmarker (2.6.1)
+      rb_sys (~> 0.9)
+
 GIT
   remote: https://github.com/whomwah/rqrcode.git
   revision: f9fa33704951158a38b3cf04311e295d3a0e947d
@@ -107,7 +115,6 @@ GEM
       xpath (~> 3.2)
     cgi (0.5.0)
     chunky_png (1.4.0)
-    commonmarker (0.23.11)
     concurrent-ruby (1.3.5)
     connection_pool (3.0.2)
     crack (1.0.0)
@@ -235,7 +242,10 @@ GEM
       zeitwerk (~> 2.6)
     rainbow (3.1.1)
     rake (13.3.0)
+    rake-compiler-dock (1.11.0)
     rb-readline (0.5.5)
+    rb_sys (0.9.124)
+      rake-compiler-dock (= 1.11.0)
     rdoc (6.14.2)
       erb
       psych (>= 4.0.0)
@@ -349,7 +359,7 @@ DEPENDENCIES
   bcrypt (~> 3.1.2)
   capybara
   cgi
-  commonmarker (>= 0.23.6, < 1.0)
+  commonmarker!
   database_cleaner
   factory_bot_rails
   faker
@@ -410,7 +420,7 @@ CHECKSUMS
   capybara (3.40.0) sha256=42dba720578ea1ca65fd7a41d163dd368502c191804558f6e0f71b391054aeef
   cgi (0.5.0) sha256=fe99f65bb2c146e294372ebb27602adbc3b4c008e9ea7038c6bd48c1ec9759da
   chunky_png (1.4.0) sha256=89d5b31b55c0cf4da3cf89a2b4ebc3178d8abe8cbaf116a1dba95668502fdcfe
-  commonmarker (0.23.11) sha256=9d1d35d358740151bce29235aebfecc63314fb57dd89a83e72d4061b4fe3d2bf
+  commonmarker (2.6.1)
   concurrent-ruby (1.3.5) sha256=813b3e37aca6df2a21a3b9f1d497f8cbab24a2b94cab325bffe65ee0f6cbebc6
   connection_pool (3.0.2) sha256=33fff5ba71a12d2aa26cb72b1db8bba2a1a01823559fb01d29eb74c286e62e0a
   crack (1.0.0) sha256=c83aefdb428cdc7b66c7f287e488c796f055c0839e6e545fec2c7047743c4a49
@@ -475,7 +485,9 @@ CHECKSUMS
   railties (8.1.1) sha256=fb0c7038b147bea41bf6697fa443ff1c5c47d3bb1eedd9ecf1bceeb90efcb868
   rainbow (3.1.1) sha256=039491aa3a89f42efa1d6dec2fc4e62ede96eb6acd95e52f1ad581182b79bc6a
   rake (13.3.0) sha256=96f5092d786ff412c62fde76f793cc0541bd84d2eb579caa529aa8a059934493
+  rake-compiler-dock (1.11.0) sha256=eab51f2cd533eb35cea6b624a75281f047123e70a64c58b607471bb49428f8c2
   rb-readline (0.5.5) sha256=9e9bd7e198bdef0822c46902f6c592b882c1f9777894a4c3dcf5b320824a8793
+  rb_sys (0.9.124) sha256=513476557b12eaf73764b3da9f8746024558fe8699bda785fb548c9aa3877ae7
   rdoc (6.14.2) sha256=9fdd44df130f856ae70cc9a264dfd659b9b40de369b16581f4ab746e42439226
   regexp_parser (2.10.0) sha256=cb6f0ddde88772cd64bff1dbbf68df66d376043fe2e66a9ef77fcb1b0c548c61
   reline (0.6.2) sha256=1dad26a6008872d59c8e05244b119347c9f2ddaf4a53dce97856cd5f30a02846
diff --git a/benchmarks/lobsters/extras/markdowner.rb b/benchmarks/lobsters/extras/markdowner.rb
index 871d7b54..96bd2863 100644
--- a/benchmarks/lobsters/extras/markdowner.rb
+++ b/benchmarks/lobsters/extras/markdowner.rb
@@ -1,17 +1,23 @@
 class Markdowner
   # opts[:allow_images] allows <img> tags
 
+  COMMONMARKER_OPTIONS = {
+    parse: { smart: true },
+    render: { unsafe: true },
+    extension: { tagfilter: true, autolink: true, strikethrough: true }
+  }.freeze
+
   def self.to_html(text, opts = {})
     if text.blank?
       return ""
     end
 
-    exts = [:tagfilter, :autolink, :strikethrough]
-    root = CommonMarker.render_doc(text.to_s, [:SMART], exts)
+    # Preprocess @mentions before markdown parsing
+    processed_text = preprocess_mentions(text.to_s)
 
-    walk_text_nodes(root) {|n| postprocess_text_node(n) }
+    html = Commonmarker.to_html(processed_text, options: COMMONMARKER_OPTIONS)
 
-    ng = Nokogiri::HTML(root.to_html([:DEFAULT], exts))
+    ng = Nokogiri::HTML(html)
 
     # change <h1>, <h2>, etc. headings to just bold tags
     ng.css("h1, h2, h3, h4, h5, h6").each do |h|
@@ -33,44 +39,13 @@ def self.to_html(text, opts = {})
     end
   end
 
-  def self.walk_text_nodes(node, &block)
-    return if node.type == :link
-    return block.call(node) if node.type == :text
-
-    node.each do |child|
-      walk_text_nodes(child, &block)
-    end
-  end
-
-  def self.postprocess_text_node(node)
-    while node
-      return unless node.string_content =~ /\B(@#{User::VALID_USERNAME})/
-      before, user, after = $`, $1, $'
-
-      node.string_content = before
-
-      if User.exists?(:username => user[1..-1])
-        link = CommonMarker::Node.new(:link)
-        link.url = Rails.application.root_url + "u/#{user[1..-1]}"
-        node.insert_after(link)
-
-        link_text = CommonMarker::Node.new(:text)
-        link_text.string_content = user
-        link.append_child(link_text)
-
-        node = link
-      else
-        node.string_content += user
-      end
-
-      if after.length > 0
-        remainder = CommonMarker::Node.new(:text)
-        remainder.string_content = after
-        node.insert_after(remainder)
-
-        node = remainder
+  def self.preprocess_mentions(text)
+    text.gsub(/\B(@#{User::VALID_USERNAME})/) do |match|
+      user = match[1..-1]
+      if User.exists?(username: user)
+        "[#{match}](#{Rails.application.root_url}u/#{user})"
       else
-        node = nil
+        match
       end
     end
   end