diff --git a/lib/AOT/runtime/superglobals_refresh.c b/lib/AOT/runtime/superglobals_refresh.c
index aaa513229..d3591d5ab 100644
--- a/lib/AOT/runtime/superglobals_refresh.c
+++ b/lib/AOT/runtime/superglobals_refresh.c
@@ -7,6 +7,14 @@
 #include <stdlib.h>
 #include <string.h>
 
+#if defined(__APPLE__) || defined(__FreeBSD__)
+#include <crt_externs.h>
+#define phpc_environ (*_NSGetEnviron())
+#else
+extern char **environ;
+#define phpc_environ environ
+#endif
+
 typedef struct __hashtable__ __hashtable__;
 typedef struct __string__ __string__;
 
@@ -86,6 +94,40 @@ static const char *request_method_for(const char *post_body)
     return ('\0' != post_body[0]) ? "POST" : "GET";
 }
 
+static int is_cgi_header_env_key(const char *key)
+{
+    if (0 == strncmp(key, "HTTP_", 5)) {
+        return 1;
+    }
+
+    return 0 == strcmp(key, "CONTENT_TYPE") || 0 == strcmp(key, "CONTENT_LENGTH");
+}
+
+static void apply_cgi_headers_from_environ(__hashtable__ *server)
+{
+    char **env;
+    char key_buf[256];
+
+    for (env = phpc_environ; NULL != env && NULL != *env; env++) {
+        const char *eq = strchr(*env, '=');
+        const char *value;
+
+        if (NULL == eq) {
+            continue;
+        }
+        if ((size_t) (eq - *env) >= sizeof(key_buf)) {
+            continue;
+        }
+        memcpy(key_buf, *env, (size_t) (eq - *env));
+        key_buf[eq - *env] = '\0';
+        if (!is_cgi_header_env_key(key_buf)) {
+            continue;
+        }
+        value = eq + 1;
+        set_string_key(server, key_buf, value);
+    }
+}
+
 static void derive_path_info(const char *script_name, const char *request_uri, char *out, size_t out_len)
 {
     char path_buf[1024];
@@ -172,6 +214,8 @@ void __superglobals__refresh(void)
         set_string_key(sg_SERVER, "PATH_INFO", path_info);
     }
 
+    apply_cgi_headers_from_environ(sg_SERVER);
+
     if (NULL == sg_COOKIE) {
         sg_COOKIE = __hashtable__alloc();
     }
diff --git a/lib/Web/DevServer.php b/lib/Web/DevServer.php
index 3f70fc820..18472231b 100644
--- a/lib/Web/DevServer.php
+++ b/lib/Web/DevServer.php
@@ -122,11 +122,7 @@ public static function handleConnection($conn, string $docroot, callable $handle
         }
 
         self::clearHttpServerKeys();
-        $httpServer = self::httpHeadersToServerVars($headers);
-        foreach ($httpServer as $key => $value) {
-            $_SERVER[$key] = $value;
-        }
-        $cgiEnv = array_merge($cgiEnv, $httpServer);
+        $cgiEnv = array_merge($cgiEnv, Superglobals::applyHttpHeaders($headers));
 
         putenv('REQUEST_METHOD='.$method);
         putenv('QUERY_STRING='.$query);
@@ -205,7 +201,7 @@ public static function readRequest($conn): ?array
      */
     public static function headerNameToServerKey(string $name): string
     {
-        return 'HTTP_'.strtoupper(str_replace('-', '_', $name));
+        return Superglobals::headerNameToServerKey($name);
     }
 
     /**
diff --git a/lib/Web/Superglobals.php b/lib/Web/Superglobals.php
index 670b0aa1a..528fd5bf1 100644
--- a/lib/Web/Superglobals.php
+++ b/lib/Web/Superglobals.php
@@ -22,6 +22,12 @@ final class Superglobals
 {
     private static ?Context $activeContext = null;
 
+    /** Maximum incoming request headers mapped into $_SERVER (issue #77). */
+    public const MAX_HTTP_HEADERS = 64;
+
+    /** Maximum length of a single header name or value after trimming. */
+    public const MAX_HTTP_HEADER_LENGTH = 8192;
+
     public const NAMES = [
         '_GET',
         '_POST',
@@ -59,6 +65,54 @@ public static function populateFromEnvironment(
         self::populateRequest($context);
     }
 
+    /**
+     * Map an HTTP header name to a CGI-style $_SERVER key (HTTP_* or CONTENT_*).
+     */
+    public static function headerNameToServerKey(string $name): string
+    {
+        $normalized = strtoupper(str_replace('-', '_', trim($name)));
+        if ('CONTENT_TYPE' === $normalized || 'CONTENT_LENGTH' === $normalized) {
+            return $normalized;
+        }
+
+        return 'HTTP_'.$normalized;
+    }
+
+    /**
+     * Apply parsed request headers to PHP $_SERVER and putenv for CGI/AOT refresh.
+     *
+     * @param array<string, string> $headers lowercase header name => value
+     *
+     * @return array<string, string> CGI env entries (HTTP_* / CONTENT_*)
+     */
+    public static function applyHttpHeaders(array $headers): array
+    {
+        $cgi = [];
+        $count = 0;
+        foreach ($headers as $name => $value) {
+            if ($count >= self::MAX_HTTP_HEADERS) {
+                break;
+            }
+            if (!is_string($name) || !is_string($value)) {
+                continue;
+            }
+            $name = trim($name);
+            $value = trim($value);
+            if ('' === $name || strlen($name) > self::MAX_HTTP_HEADER_LENGTH
+                || strlen($value) > self::MAX_HTTP_HEADER_LENGTH
+                || str_contains($value, "\r") || str_contains($value, "\n")) {
+                continue;
+            }
+            $key = self::headerNameToServerKey($name);
+            $_SERVER[$key] = $value;
+            putenv($key.'='.$value);
+            $cgi[$key] = $value;
+            ++$count;
+        }
+
+        return $cgi;
+    }
+
     private static function populateGet(Context $context, string $queryString): void
     {
         $get = $context->ensureSuperglobal('_GET');
@@ -113,11 +167,11 @@ private static function populateServer(
         self::setStringEntry($server, 'GATEWAY_INTERFACE', 'CGI/1.1');
         self::setStringEntry($server, 'SERVER_SOFTWARE', 'PHP-Compiler-VM');
 
-        foreach ($_SERVER as $key => $value) {
+        foreach (array_merge($_ENV, $_SERVER) as $key => $value) {
             if (!is_string($key) || !is_string($value)) {
                 continue;
             }
-            if (str_starts_with($key, 'HTTP_')) {
+            if (str_starts_with($key, 'HTTP_') || str_starts_with($key, 'CONTENT_')) {
                 self::setStringEntry($server, $key, $value);
             }
         }
diff --git a/test/aot/RuntimeSuperglobalRefreshTest.php b/test/aot/RuntimeSuperglobalRefreshTest.php
index db8547aba..d7047a3ad 100644
--- a/test/aot/RuntimeSuperglobalRefreshTest.php
+++ b/test/aot/RuntimeSuperglobalRefreshTest.php
@@ -78,6 +78,57 @@ public function testTwoRequestsDifferentQueryString(): void
         @unlink($outfile);
     }
 
+    public function testHttpHostFromCgiEnvironment(): void
+    {
+        $source = <<<'PHP'
+<?php
+declare(strict_types=1);
+header('Content-Type: text/plain; charset=UTF-8');
+echo $_SERVER['HTTP_HOST'], $_SERVER['HTTP_X_CUSTOM'];
+PHP;
+
+        $outfile = tempnam(sys_get_temp_dir(), 'phpc_http_hdr_');
+        $this->assertNotFalse($outfile);
+        unlink($outfile);
+
+        $repoRoot = dirname(__DIR__, 2);
+        $env = $this->llvmProcessEnv($repoRoot);
+        $descriptorSpec = [
+            0 => ['pipe', 'r'],
+            1 => ['pipe', 'w'],
+            2 => ['pipe', 'w'],
+        ];
+
+        $compile = proc_open(
+            array_merge(
+                self::llvmEnvPrefix(),
+                self::phpCommand(),
+                [$this->compileBin, '-o', $outfile]
+            ),
+            $descriptorSpec,
+            $pipes,
+            $repoRoot,
+            $env
+        );
+        fwrite($pipes[0], $source);
+        fclose($pipes[0]);
+        $compileErr = stream_get_contents($pipes[2]);
+        fclose($pipes[1]);
+        fclose($pipes[2]);
+        proc_close($compile);
+        $this->assertFileExists($outfile, trim($compileErr !== false ? $compileErr : ''));
+
+        $runEnv = $env;
+        $runEnv['HTTP_HOST'] = 'example.test';
+        $runEnv['HTTP_X_CUSTOM'] = '1';
+        $runEnv['SCRIPT_NAME'] = '/index.php';
+        $runEnv['REQUEST_URI'] = '/index.php';
+        $output = $this->runBinary($outfile, $runEnv);
+        $this->assertStringContainsString('example.test1', $output);
+
+        @unlink($outfile);
+    }
+
     /**
      * @param array<string, string> $env
      */
diff --git a/test/unit/Web/SuperglobalsHttpHeadersTest.php b/test/unit/Web/SuperglobalsHttpHeadersTest.php
new file mode 100644
index 000000000..8f0c85f42
--- /dev/null
+++ b/test/unit/Web/SuperglobalsHttpHeadersTest.php
@@ -0,0 +1,47 @@
+<?php
+
+declare(strict_types=1);
+
+namespace PHPCompiler;
+
+use PHPCompiler\Web\Superglobals;
+use PHPUnit\Framework\TestCase;
+
+/**
+ * Issue #193: HTTP request headers mapped to $_SERVER HTTP_* keys.
+ */
+final class SuperglobalsHttpHeadersTest extends TestCase
+{
+    protected function tearDown(): void
+    {
+        foreach (array_keys($_SERVER) as $key) {
+            if (str_starts_with($key, 'HTTP_') || str_starts_with($key, 'CONTENT_')) {
+                unset($_SERVER[$key]);
+                putenv($key);
+            }
+        }
+    }
+
+    public function testHeaderNameToServerKey(): void
+    {
+        $this->assertSame('HTTP_HOST', Superglobals::headerNameToServerKey('Host'));
+        $this->assertSame('HTTP_X_CUSTOM', Superglobals::headerNameToServerKey('X-Custom'));
+        $this->assertSame('CONTENT_TYPE', Superglobals::headerNameToServerKey('Content-Type'));
+        $this->assertSame('CONTENT_LENGTH', Superglobals::headerNameToServerKey('content-length'));
+    }
+
+    public function testApplyHttpHeadersSetsCgiEnvironment(): void
+    {
+        $cgi = Superglobals::applyHttpHeaders([
+            'host' => 'example.test',
+            'x-custom' => '1',
+        ]);
+
+        $this->assertSame([
+            'HTTP_HOST' => 'example.test',
+            'HTTP_X_CUSTOM' => '1',
+        ], $cgi);
+        $this->assertSame('example.test', $_SERVER['HTTP_HOST'] ?? '');
+        $this->assertSame('1', getenv('HTTP_X_CUSTOM'));
+    }
+}