diff --git a/src/Symfony/Component/HttpClient/CurlHttpClient.php b/src/Symfony/Component/HttpClient/CurlHttpClient.php
index 67a6c1dddd5d8..ba3191c37c340 100644
--- a/src/Symfony/Component/HttpClient/CurlHttpClient.php
+++ b/src/Symfony/Component/HttpClient/CurlHttpClient.php
@@ -236,6 +236,10 @@ public function request(string $method, string $url, array $options = []): Respo
         }
 
         if (!\is_string($body)) {
+            if (isset($options['auth_ntlm'])) {
+                $curlopts[\CURLOPT_FORBID_REUSE] = true; // Reusing NTLM connections requires seeking capability, which only string bodies support
+            }
+
             if (\is_resource($body)) {
                 $curlopts[\CURLOPT_INFILE] = $body;
             } else {
diff --git a/src/Symfony/Component/HttpClient/HttplugClient.php b/src/Symfony/Component/HttpClient/HttplugClient.php
index 8e1dc1c4cb9e3..dad01dcc89c8e 100644
--- a/src/Symfony/Component/HttpClient/HttplugClient.php
+++ b/src/Symfony/Component/HttpClient/HttplugClient.php
@@ -224,23 +224,44 @@ private function sendPsr7Request(RequestInterface $request, ?bool $buffer = null
     {
         try {
             $body = $request->getBody();
+            $headers = $request->getHeaders();
 
-            if ($body->isSeekable()) {
-                try {
-                    $body->seek(0);
-                } catch (\RuntimeException) {
-                    // ignore
-                }
+            $size = $request->getHeader('content-length')[0] ?? -1;
+            if (0 > $size && 0 < $size = $body->getSize() ?? -1) {
+                $headers['Content-Length'] = [$size];
             }
 
-            $headers = $request->getHeaders();
-            if (!$request->hasHeader('content-length') && 0 <= $size = $body->getSize() ?? -1) {
-                $headers['Content-Length'] = [$size];
+            if (0 === $size) {
+                $body = '';
+            } elseif (0 < $size && $size < 1 << 21) {
+                if ($body->isSeekable()) {
+                    try {
+                        $body->seek(0);
+                    } catch (\RuntimeException) {
+                        // ignore
+                    }
+                }
+
+                $body = $body->getContents();
+            } else {
+                $body = static function (int $size) use ($body) {
+                    if ($body->isSeekable()) {
+                        try {
+                            $body->seek(0);
+                        } catch (\RuntimeException) {
+                            // ignore
+                        }
+                    }
+
+                    while (!$body->eof()) {
+                        yield $body->read($size);
+                    }
+                };
             }
 
             $options = [
                 'headers' => $headers,
-                'body' => static fn (int $size) => $body->read($size),
+                'body' => $body,
                 'buffer' => $buffer,
             ];
 
diff --git a/src/Symfony/Component/HttpClient/Psr18Client.php b/src/Symfony/Component/HttpClient/Psr18Client.php
index a2a19236e8f67..5ab4a8d3ce41d 100644
--- a/src/Symfony/Component/HttpClient/Psr18Client.php
+++ b/src/Symfony/Component/HttpClient/Psr18Client.php
@@ -88,23 +88,44 @@ public function sendRequest(RequestInterface $request): ResponseInterface
     {
         try {
             $body = $request->getBody();
+            $headers = $request->getHeaders();
 
-            if ($body->isSeekable()) {
-                try {
-                    $body->seek(0);
-                } catch (\RuntimeException) {
-                    // ignore
-                }
+            $size = $request->getHeader('content-length')[0] ?? -1;
+            if (0 > $size && 0 < $size = $body->getSize() ?? -1) {
+                $headers['Content-Length'] = [$size];
             }
 
-            $headers = $request->getHeaders();
-            if (!$request->hasHeader('content-length') && 0 <= $size = $body->getSize() ?? -1) {
-                $headers['Content-Length'] = [$size];
+            if (0 === $size) {
+                $body = '';
+            } elseif (0 < $size && $size < 1 << 21) {
+                if ($body->isSeekable()) {
+                    try {
+                        $body->seek(0);
+                    } catch (\RuntimeException) {
+                        // ignore
+                    }
+                }
+
+                $body = $body->getContents();
+            } else {
+                $body = static function (int $size) use ($body) {
+                    if ($body->isSeekable()) {
+                        try {
+                            $body->seek(0);
+                        } catch (\RuntimeException) {
+                            // ignore
+                        }
+                    }
+
+                    while (!$body->eof()) {
+                        yield $body->read($size);
+                    }
+                };
             }
 
             $options = [
                 'headers' => $headers,
-                'body' => static fn (int $size) => $body->read($size),
+                'body' => $body,
             ];
 
             if ('1.0' === $request->getProtocolVersion()) {