diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 56ded6f..faec14e 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -18,6 +18,8 @@ jobs:
         ruby: ${{ fromJson(needs.ruby-versions.outputs.versions) }}
         os: [ ubuntu-latest, macos-latest, windows-latest ]
     runs-on: ${{ matrix.os }}
+    env:
+      BUNDLE_WITHOUT: sig
     steps:
     - uses: actions/checkout@v7
     - name: Set up Ruby
@@ -26,11 +28,9 @@ jobs:
         ruby-version: ${{ matrix.ruby }}
     - name: Install dependencies
       run: bundle install
-      env:
-        BUNDLE_WITHOUT: sig
     - name: Run test
-      run: rake test
+      run: bundle exec rake test
     - name: Build
-      run: rake build
+      run: bundle exec rake build
       env:
         LANG: C
diff --git a/lib/net/http/response.rb b/lib/net/http/response.rb
index 0b5b326..4d8b938 100644
--- a/lib/net/http/response.rb
+++ b/lib/net/http/response.rb
@@ -155,11 +155,17 @@ def read_new(sock)   #:nodoc: internal use only
       res
     end
 
+    def read_line(sock, limit, ignore_eof = false)   #:nodoc: internal use only
+      sock.readuntil("\n", ignore_eof, limit: limit)
+    rescue Net::ReadLimitExceeded
+      raise Net::HTTPBadResponse, 'response line too long'
+    end
+
     private
     # :stopdoc:
 
     def read_status_line(sock)
-      str = sock.readline
+      str = read_line(sock, MAX_RESPONSE_HEADER_LENGTH).chop
       m = /\AHTTP(?:\/(\d+\.\d+))?\s+(\d\d\d)(?:\s+(.*))?\z/in.match(str) or
         raise Net::HTTPBadResponse, "wrong status line: #{str.dump}"
       m.captures
@@ -175,7 +181,7 @@ def each_response_header(sock)
       key = value = nil
       remaining = MAX_RESPONSE_HEADER_LENGTH
       while true
-        line = sock.readuntil("\n", true)
+        line = read_line(sock, MAX_RESPONSE_HEADER_LENGTH, true)
         remaining -= line.bytesize
         raise Net::HTTPBadResponse, 'response header too large' if remaining < 0
         line = line.sub(/\s+\z/, '')
@@ -630,7 +636,7 @@ def read_body_0(dest)
   def read_chunked(dest, chunk_data_io) # :nodoc:
     total = 0
     while true
-      line = @socket.readline
+      line = self.class.read_line(@socket, MAX_RESPONSE_HEADER_LENGTH).chop
       hexlen = line.slice(/[0-9a-fA-F]+/) or
           raise Net::HTTPBadResponse, "wrong chunk size line: #{line}"
       len = hexlen.hex
@@ -642,7 +648,7 @@ def read_chunked(dest, chunk_data_io) # :nodoc:
         @socket.read 2   # \r\n
       end
     end
-    until @socket.readline.empty?
+    until self.class.read_line(@socket, MAX_RESPONSE_HEADER_LENGTH).chop.empty?
       # none
     end
   end
diff --git a/net-http.gemspec b/net-http.gemspec
index d59d5c3..318f9dc 100644
--- a/net-http.gemspec
+++ b/net-http.gemspec
@@ -35,5 +35,6 @@ Gem::Specification.new do |spec|
   spec.bindir        = "exe"
   spec.require_paths = ["lib"]
 
+  spec.add_dependency "net-protocol", ">= 0.3.0"
   spec.add_dependency "uri", ">= 0.11.1"
 end
diff --git a/test/net/http/test_http.rb b/test/net/http/test_http.rb
index e5028d4..097fda6 100644
--- a/test/net/http/test_http.rb
+++ b/test/net/http/test_http.rb
@@ -1262,17 +1262,18 @@ def closed?
     end
     def write(_)
     end
-    def readline
+    def readuntil(terminator, ignore_eof = false, limit: nil)
+      raise "unexpected terminator #{terminator.dump}" unless terminator == "\n"
+      # A header read ends the headers at once. Every other read is the
+      # status line of a fresh attempt, which is what count measures.
+      return "" if ignore_eof
       @count += 1
       if @success_after && @success_after <= @count
-        "HTTP/1.1 200 OK"
+        "HTTP/1.1 200 OK\n"
       else
         raise Errno::ECONNRESET
       end
     end
-    def readuntil(*_)
-      ""
-    end
     def read_all(_)
     end
   end
diff --git a/test/net/http/test_httpresponse.rb b/test/net/http/test_httpresponse.rb
index 7e7ae8a..7f9ea94 100644
--- a/test/net/http/test_httpresponse.rb
+++ b/test/net/http/test_httpresponse.rb
@@ -25,9 +25,10 @@ def test_response_header_too_large
     count.times { |i| headers << "X-Pad-#{i}: #{big_value}\n" }
     headers << "\nhello\n"
     io = dummy_io(headers)
-    assert_raise(Net::HTTPBadResponse) do
+    e = assert_raise(Net::HTTPBadResponse) do
       Net::HTTPResponse.read_new(io)
     end
+    assert_equal 'response header too large', e.message
   end
 
   def test_response_header_within_limit
@@ -42,6 +43,40 @@ def test_response_header_within_limit
     end
   end
 
+  def test_status_line_too_long
+    io = endless_io("HTTP/1.1 200 ")
+    assert_raise(Net::HTTPBadResponse) do
+      Net::HTTPResponse.read_new(io)
+    end
+  end
+
+  def test_response_header_line_too_long
+    io = endless_io("HTTP/1.1 200 OK\nX-Foo: ")
+    assert_raise(Net::HTTPBadResponse) do
+      Net::HTTPResponse.read_new(io)
+    end
+  end
+
+  def test_chunk_size_line_too_long
+    io = endless_io("HTTP/1.1 200 OK\nTransfer-Encoding: chunked\n\n")
+    res = Net::HTTPResponse.read_new(io)
+    assert_raise(Net::HTTPBadResponse) do
+      res.reading_body io, true do
+        res.read_body
+      end
+    end
+  end
+
+  def test_chunk_trailer_line_too_long
+    io = endless_io("HTTP/1.1 200 OK\nTransfer-Encoding: chunked\n\n0\n")
+    res = Net::HTTPResponse.read_new(io)
+    assert_raise(Net::HTTPBadResponse) do
+      res.reading_body io, true do
+        res.read_body
+      end
+    end
+  end
+
   def test_multiline_header
     io = dummy_io(<<EOS)
 HTTP/1.1 200 OK
@@ -775,4 +810,33 @@ def dummy_io(str)
 
     Net::BufferedIO.new(StringIO.new(str))
   end
+
+  # Yields the given prefix, then streams 'a' without EOF. Stops with an
+  # error well past the limit under test so that a regression fails the
+  # test instead of looping until the machine runs out of memory.
+  class EndlessDataIO
+    SAFETY_LIMIT = Net::HTTPResponse::MAX_RESPONSE_HEADER_LENGTH * 2
+
+    def initialize(prefix)
+      @buf = prefix.b
+      @served = 0
+    end
+
+    def read_nonblock(size, buf = nil, exception: false)
+      @served += size
+      raise "read #{@served} bytes without hitting the line limit" if
+        @served > SAFETY_LIMIT
+      @buf << 'a' * (size - @buf.bytesize) if @buf.bytesize < size
+      s = @buf.slice!(0, size)
+      buf ? buf.replace(s) : s
+    end
+
+    def closed?
+      false
+    end
+  end
+
+  def endless_io(prefix)
+    Net::BufferedIO.new(EndlessDataIO.new(prefix.gsub(/\n/, "\r\n")))
+  end
 end