CVE-2023-26130 (published 2023-05-30T05:15Z)

Versions of the package yhirose/cpp-httplib before 0.12.4 are vulnerable to CRLF Injection when untrusted user input is used to set the content-type header in the HTTP .Patch, .Post, .Put and .Delete requests. This can lead to logical errors and other misbehaviors.\r\r**Note:** This issue is present due to an incomplete fix for [CVE-2020-11709](https://security.snyk.io/vuln/SNYK-UNMANAGED-YHIROSECPPHTTPLIB-2366507).

CVSS v3 base score: 8.8, HIGH (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H)

Weakness information:
cwe_id: CWE-74
cwe_name: Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')
description: The product constructs all or part of a command, data structure, or record using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify how it is parsed or interpreted when it is sent to a downstream component.
extended_description: Software or other automated logic has certain assumptions about what constitutes data and control respectively. It is the lack of verification of these assumptions for user-controlled input that leads to injection problems. Injection problems encompass a wide variety of issues -- all mitigated in very different ways and usually attempted in order to alter the control flow of the process. For this reason, the most effective way to discuss these weaknesses is to note the distinct features that classify them as injection weaknesses. The most important issue to note is that all injection problems share one thing in common -- i.e., they allow for the injection of control plane data into the user-controlled data plane. This means that the execution of the process may be altered by sending code in through legitimate data channels, using no other mechanism. While buffer overflows, and many other flaws, involve the use of some further issue to gain execution, injection problems need only for the data to be parsed.
         

Fix information:
repo_url: https://github.com/yhirose/cpp-httplib
commit_details: repo_url: https://github.com/yhirose/cpp-httplib
author: yhirose
author_date: 2023-05-22 22:56:16+09:00
msg: Fix more CRLF injection problems.
repository: repo_url: https://github.com/yhirose/cpp-httplib
repo_name: yhirose/cpp-httplib
description: A C++ header-only HTTP/HTTPS server and client library
repo_language: C++
owner: yhirose
file_changes: filename: httplib.h
change_type: ModificationType.MODIFY
diff: @@ -5925,8 +5925,8 @@ inline void Server::apply_ranges(const Request &req, Response &res,
       res.headers.erase(it);
     }
 
-    res.headers.emplace("Content-Type",
-                        "multipart/byteranges; boundary=" + boundary);
+    res.set_header("Content-Type",
+                   "multipart/byteranges; boundary=" + boundary);
   }
 
   auto type = detail::encoding_type(req, res);
@@ -6616,32 +6616,32 @@ inline bool ClientImpl::write_request(Stream &strm, Request &req,
   // Prepare additional headers
   if (close_connection) {
     if (!req.has_header("Connection")) {
-      req.headers.emplace("Connection", "close");
+      req.set_header("Connection", "close");
     }
   }
 
   if (!req.has_header("Host")) {
     if (is_ssl()) {
       if (port_ == 443) {
-        req.headers.emplace("Host", host_);
+        req.set_header("Host", host_);
       } else {
-        req.headers.emplace("Host", host_and_port_);
+        req.set_header("Host", host_and_port_);
       }
     } else {
       if (port_ == 80) {
-        req.headers.emplace("Host", host_);
+        req.set_header("Host", host_);
       } else {
-        req.headers.emplace("Host", host_and_port_);
+        req.set_header("Host", host_and_port_);
       }
     }
   }
 
-  if (!req.has_header("Accept")) { req.headers.emplace("Accept", "*/*"); }
+  if (!req.has_header("Accept")) { req.set_header("Accept", "*/*"); }
 
 #ifndef CPPHTTPLIB_NO_DEFAULT_USER_AGENT
   if (!req.has_header("User-Agent")) {
     auto agent = std::string("cpp-httplib/") + CPPHTTPLIB_VERSION;
-    req.headers.emplace("User-Agent", agent);
+    req.set_header("User-Agent", agent);
   }
 #endif
 
@@ -6650,23 +6650,23 @@ inline bool ClientImpl::write_request(Stream &strm, Request &req,
       if (!req.is_chunked_content_provider_) {
         if (!req.has_header("Content-Length")) {
           auto length = std::to_string(req.content_length_);
-          req.headers.emplace("Content-Length", length);
+          req.set_header("Content-Length", length);
         }
       }
     } else {
       if (req.method == "POST" || req.method == "PUT" ||
           req.method == "PATCH") {
-        req.headers.emplace("Content-Length", "0");
+        req.set_header("Content-Length", "0");
       }
     }
   } else {
     if (!req.has_header("Content-Type")) {
-      req.headers.emplace("Content-Type", "text/plain");
+      req.set_header("Content-Type", "text/plain");
     }
 
     if (!req.has_header("Content-Length")) {
       auto length = std::to_string(req.body.size());
-      req.headers.emplace("Content-Length", length);
+      req.set_header("Content-Length", length);
     }
   }
 
@@ -6734,12 +6734,10 @@ inline std::unique_ptr<Response> ClientImpl::send_with_content_provider(
     ContentProvider content_provider,
     ContentProviderWithoutLength content_provider_without_length,
     const std::string &content_type, Error &error) {
-  if (!content_type.empty()) {
-    req.headers.emplace("Content-Type", content_type);
-  }
+  if (!content_type.empty()) { req.set_header("Content-Type", content_type); }
 
 #ifdef CPPHTTPLIB_ZLIB_SUPPORT
-  if (compress_) { req.headers.emplace("Content-Encoding", "gzip"); }
+  if (compress_) { req.set_header("Content-Encoding", "gzip"); }
 #endif
 
 #ifdef CPPHTTPLIB_ZLIB_SUPPORT
@@ -6800,7 +6798,7 @@ inline std::unique_ptr<Response> ClientImpl::send_with_content_provider(
       req.content_provider_ = detail::ContentProviderAdapter(
           std::move(content_provider_without_length));
       req.is_chunked_content_provider_ = true;
-      req.headers.emplace("Transfer-Encoding", "chunked");
+      req.set_header("Transfer-Encoding", "chunked");
     } else {
       req.body.assign(body, content_length);
       ;
@@ -7423,9 +7421,7 @@ inline Result ClientImpl::Delete(const std::string &path,
   req.headers = headers;
   req.path = path;
 
-  if (!content_type.empty()) {
-    req.headers.emplace("Content-Type", content_type);
-  }
+  if (!content_type.empty()) { req.set_header("Content-Type", content_type); }
   req.body.assign(body, content_length);
 
   return send_(std::move(req));

programming_language: C++
filename: test.cc
change_type: ModificationType.MODIFY
diff: @@ -6116,3 +6116,49 @@ TEST(RedirectTest, RedirectToUrlWithQueryParameters) {
     EXPECT_EQ("val&key2=val2", res->body);
   }
 }
+
+TEST(VulnerabilityTest, CRLFInjection) {
+  Server svr;
+
+  svr.Post("/test1", [](const Request &/*req*/, Response &res) {
+    res.set_content("Hello 1", "text/plain");
+  });
+
+  svr.Delete("/test2", [](const Request &/*req*/, Response &res) {
+    res.set_content("Hello 2", "text/plain");
+  });
+
+  svr.Put("/test3", [](const Request &/*req*/, Response &res) {
+    res.set_content("Hello 3", "text/plain");
+  });
+
+  svr.Patch("/test4", [](const Request &/*req*/, Response &res) {
+    res.set_content("Hello 4", "text/plain");
+  });
+
+  svr.set_logger([](const Request &req, const Response & /*res*/) {
+    for (const auto &x : req.headers) {
+      auto key = x.first;
+      EXPECT_STRNE("evil", key.c_str());
+    }
+  });
+
+  auto thread = std::thread([&]() { svr.listen(HOST, PORT); });
+  auto se = detail::scope_exit([&] {
+    svr.stop();
+    thread.join();
+    ASSERT_FALSE(svr.is_running());
+  });
+
+  std::this_thread::sleep_for(std::chrono::seconds(1));
+
+  {
+    Client cli(HOST, PORT);
+
+    cli.Post("/test1", "A=B",
+             "application/x-www-form-urlencoded\r\nevil: hello1");
+    cli.Delete("/test2", "A=B", "text/plain\r\nevil: hello2");
+    cli.Put("/test3", "text", "text/plain\r\nevil: hello3");
+    cli.Patch("/test4", "content", "text/plain\r\nevil: hello4");
+  }
+}

programming_language: C++