diff --git a/src/plugins/imageformats/tga/qtgafile.cpp b/src/plugins/imageformats/tga/qtgafile.cpp
index 5d086c6..3961c16 100644
--- a/src/plugins/imageformats/tga/qtgafile.cpp
+++ b/src/plugins/imageformats/tga/qtgafile.cpp
@@ -220,9 +220,18 @@ QImage QTgaFile::readImage()
 
     int offset = mHeader[IdLength];  // Mostly always zero
 
-    // Even in TrueColor files a color pallette may be present
-    if (mHeader[ColorMapType] == 1)
-        offset += littleEndianInt(&mHeader[CMapLength]) * littleEndianInt(&mHeader[CMapDepth]);
+    // Even in TrueColor files a color palette may be present so we have to check it here
+    // even we only support image type 2 (= uncompressed true-color image)
+    if (mHeader[ColorMapType] == 1) {
+        int cmapDepth = mHeader[CMapDepth];
+        if (cmapDepth == 15)    // 15 bit is stored as 16 bit + ignoring the highest bit (no alpha)
+            cmapDepth = 16;
+        if (cmapDepth != 16 && cmapDepth != 24 && cmapDepth != 32) {
+            mErrorMessage = tr("Invalid color map depth (%1)").arg(cmapDepth);
+            return {};
+        }
+        offset += littleEndianInt(&mHeader[CMapLength]) * cmapDepth / 8;
+    }
 
     mDevice->seek(HeaderSize + offset);
 
diff --git a/src/plugins/imageformats/tiff/qtiffhandler.cpp b/src/plugins/imageformats/tiff/qtiffhandler.cpp
index ac8956c..79be154 100644
--- a/src/plugins/imageformats/tiff/qtiffhandler.cpp
+++ b/src/plugins/imageformats/tiff/qtiffhandler.cpp
@@ -38,11 +38,15 @@
 ****************************************************************************/
 
 #include "qtiffhandler_p.h"
-#include <qvariant.h>
 #include <qcolorspace.h>
 #include <qdebug.h>
 #include <qimage.h>
 #include <qglobal.h>
+#include <qvariant.h>
+#include <qvarlengtharray.h>
+#include <qbuffer.h>
+#include <qfiledevice.h>
+
 extern "C" {
 #include "tiffio.h"
 }
@@ -90,13 +94,33 @@ toff_t qtiffSizeProc(thandle_t fd)
     return static_cast<QIODevice *>(fd)->size();
 }
 
-int qtiffMapProc(thandle_t /*fd*/, tdata_t* /*pbase*/, toff_t* /*psize*/)
+int qtiffMapProc(thandle_t fd, void **base, toff_t *size)
 {
+    QIODevice *device = static_cast<QIODevice *>(fd);
+
+    QFileDevice *file = qobject_cast<QFileDevice *>(device);
+    if (file) {
+        *base = file->map(0, file->size());
+        if (*base != nullptr) {
+            *size = file->size();
+            return 1;
+        }
+    } else {
+        QBuffer *buf = qobject_cast<QBuffer *>(device);
+        if (buf) {
+            *base = const_cast<char *>(buf->data().constData());
+            *size = buf->size();
+            return 1;
+        }
+    }
     return 0;
 }
 
-void qtiffUnmapProc(thandle_t /*fd*/, tdata_t /*base*/, toff_t /*size*/)
+void qtiffUnmapProc(thandle_t fd, void *base, toff_t /*size*/)
 {
+    QFileDevice *file = qobject_cast<QFileDevice *>(static_cast<QIODevice *>(fd));
+    if (file && base)
+        file->unmap(static_cast<uchar *>(base));
 }
 
 
diff --git a/src/plugins/imageformats/webp/CMakeLists.txt b/src/plugins/imageformats/webp/CMakeLists.txt
index 25aa0c9..fbbcc1c 100644
--- a/src/plugins/imageformats/webp/CMakeLists.txt
+++ b/src/plugins/imageformats/webp/CMakeLists.txt
@@ -30,6 +30,7 @@ qt_internal_extend_target(QWebpPlugin CONDITION QT_FEATURE_system_webp
 qt_internal_extend_target(QWebpPlugin CONDITION NOT QT_FEATURE_system_webp
     SOURCES
         ../../../3rdparty/libwebp/sharpyuv/sharpyuv.c
+        ../../../3rdparty/libwebp/sharpyuv/sharpyuv_cpu.c
         ../../../3rdparty/libwebp/sharpyuv/sharpyuv_csp.c
         ../../../3rdparty/libwebp/sharpyuv/sharpyuv_dsp.c
         ../../../3rdparty/libwebp/sharpyuv/sharpyuv_gamma.c
diff --git a/src/plugins/imageformats/webp/qwebphandler.cpp b/src/plugins/imageformats/webp/qwebphandler.cpp
index 82d38cb..d02eb05 100644
--- a/src/plugins/imageformats/webp/qwebphandler.cpp
+++ sb/src/plugins/imageformats/webp/qwebphandler.cpp
@@ -45,6 +45,7 @@
 #include <qdebug.h>
 #include <qpainter.h>
 #include <qvariant.h>
+#include <QtEndian>
 
 static const int riffHeaderSize = 12; // RIFF_HEADER_SIZE from webp/format_constants.h
 
@@ -102,21 +103,23 @@ bool QWebpHandler::ensureScanned() const
 
     m_scanState = ScanError;
 
-    if (device()->isSequential()) {
-        qWarning() << "Sequential devices are not supported";
+    QWebpHandler *that = const_cast<QWebpHandler *>(this);
+    const int headerBytesNeeded = sizeof(WebPBitstreamFeatures);
+    QByteArray header = device()->peek(headerBytesNeeded);
+    if (header.size() < headerBytesNeeded)
         return false;
-    }
 
-    qint64 oldPos = device()->pos();
-    device()->seek(0);
-
-    QWebpHandler *that = const_cast<QWebpHandler *>(this);
-    QByteArray header = device()->peek(sizeof(WebPBitstreamFeatures));
+    // We do no random access during decoding, just a readAll() of the whole image file. So if
+    // if it is all available already, we can accept a sequential device. The riff header contains
+    // the file size minus 8 bytes header
+    qint64 byteSize = qFromLittleEndian<quint32>(header.constData() + 4);
+    if (device()->isSequential() && device()->bytesAvailable() < byteSize + 8) {
+        qWarning() << "QWebpHandler: Insufficient data available in sequential device";
+        return false;
+    }
     if (WebPGetFeatures((const uint8_t*)header.constData(), header.size(), &(that->m_features)) == VP8_STATUS_OK) {
         if (m_features.has_animation) {
             // For animation, we have to read and scan whole file to determine loop count and images count
-            device()->seek(oldPos);
-
             if (that->ensureDemuxer()) {
                 that->m_loop = WebPDemuxGetI(m_demuxer, WEBP_FF_LOOP_COUNT);
                 that->m_frameCount = WebPDemuxGetI(m_demuxer, WEBP_FF_FRAME_COUNT);
@@ -126,17 +129,13 @@ bool QWebpHandler::ensureScanned() const
                 if (that->m_features.has_alpha)
                     that->m_composited->fill(Qt::transparent);
 
-                // We do not reset device position since we have read in all data
                 m_scanState = ScanSuccess;
-                return true;
             }
         } else {
             m_scanState = ScanSuccess;
         }
     }
 
-    device()->seek(oldPos);
-
     return m_scanState == ScanSuccess;
 }
 
@@ -159,7 +158,7 @@ bool QWebpHandler::ensureDemuxer()
 
 bool QWebpHandler::read(QImage *image)
 {
-    if (!ensureScanned() || device()->isSequential() || !ensureDemuxer())
+    if (!ensureScanned() || !ensureDemuxer())
         return false;
 
     QRect prevFrameRect;
Submodule qtlocation b6d96559..5b27b892:
Submodule src/3rdparty/mapbox-gl-native d3101bbc...4c88f2c0 (commits not present)