diff --git a/modules/imgcodecs/src/grfmt_bmp.cpp b/modules/imgcodecs/src/grfmt_bmp.cpp
index 77201b3af1..c8b604166c 100644
--- a/modules/imgcodecs/src/grfmt_bmp.cpp
+++ b/modules/imgcodecs/src/grfmt_bmp.cpp
@@ -233,9 +233,13 @@ bool  BmpDecoder::readData( Mat& img )
     bool color = img.channels() > 1;
     uchar  gray_palette[256] = {0};
     bool   result = false;
-    int  src_pitch = ((m_width*(m_bpp != 15 ? m_bpp : 16) + 7)/8 + 3) & -4;
     int  nch = color ? 3 : 1;
-    int  y, width3 = m_width*nch;
+
+    const int effective_bpp = (m_bpp != 15) ? m_bpp : 16;
+    const RowPitchParams pitch_params = calculateRowPitch(m_width, effective_bpp, 4, "BMP");
+    const int src_pitch = pitch_params.src_pitch;
+    const int width3 = calculateRowSize(m_width, nch, "BMP");
+    int y;
 
     if( m_offset < 0 || !m_strm.isOpened())
         return false;
@@ -255,7 +259,9 @@ bool  BmpDecoder::readData( Mat& img )
         {
             CvtPaletteToGray( m_palette, gray_palette, 1 << m_bpp );
         }
-        _bgr.allocate(m_width*3 + 32);
+        const size_t bgr_size = static_cast<size_t>(m_width) * 3 + 32;
+        CV_CheckLT(bgr_size, MAX_IMAGE_ROW_SIZE, "BMP: bgr buffer size exceeds maximum allowed size");
+        _bgr.allocate(bgr_size);
     }
     uchar *src = _src.data(), *bgr = _bgr.data();
 
diff --git a/modules/imgcodecs/src/grfmt_sunras.cpp b/modules/imgcodecs/src/grfmt_sunras.cpp
index 0dd31b3b1a..06d55d2c44 100644
--- a/modules/imgcodecs/src/grfmt_sunras.cpp
+++ b/modules/imgcodecs/src/grfmt_sunras.cpp
@@ -133,10 +133,13 @@ bool  SunRasterDecoder::readData( Mat& img )
     size_t step = img.step;
     uchar  gray_palette[256] = {0};
     bool   result = false;
-    int  src_pitch = ((m_width*m_bpp + 7)/8 + 1) & -2;
     int  nch = color ? 3 : 1;
-    int  width3 = m_width*nch;
-    int  y;
+
+    const RowPitchParams pitch_params = calculateRowPitch(m_width, m_bpp, 2, "SunRaster");
+    const int src_pitch = pitch_params.src_pitch;
+    const size_t bytes_per_row = pitch_params.bytes_per_row;
+    const int width3 = calculateRowSize(m_width, nch, "SunRaster");
+    int y;
 
     if( m_offset < 0 || !m_strm.isOpened())
         return false;
@@ -169,7 +172,7 @@ bool  SunRasterDecoder::readData( Mat& img )
             }
             else
             {
-                uchar* line_end = src + (m_width*m_bpp + 7)/8;
+                uchar* line_end = src + bytes_per_row;
                 uchar* tsrc = src;
                 y = 0;
 
diff --git a/modules/imgcodecs/src/utils.cpp b/modules/imgcodecs/src/utils.cpp
index 3b597fe61c..5c3127792a 100644
--- a/modules/imgcodecs/src/utils.cpp
+++ b/modules/imgcodecs/src/utils.cpp
@@ -51,6 +51,37 @@ int validateToInt(size_t sz)
     return valueInt;
 }
 
+RowPitchParams calculateRowPitch(int width, int bpp, int alignment, const char* format_name)
+{
+    CV_Assert(width > 0 && bpp > 0 && alignment > 0);
+    CV_Assert((alignment & (alignment - 1)) == 0);  // must be power of 2
+
+    const size_t bits_per_row = static_cast<size_t>(width) * static_cast<size_t>(bpp);
+    const size_t bytes_per_row = (bits_per_row + 7) / 8;
+    const size_t aligned_pitch = (bytes_per_row + alignment - 1) & ~static_cast<size_t>(alignment - 1);
+
+    if (aligned_pitch >= MAX_IMAGE_ROW_SIZE)
+        CV_Error(cv::Error::StsOutOfRange,
+                 cv::format("%s: src_pitch exceeds maximum allowed size", format_name));
+
+    RowPitchParams result;
+    result.src_pitch = validateToInt(aligned_pitch);
+    result.bytes_per_row = bytes_per_row;
+    return result;
+}
+
+int calculateRowSize(int width, int nch, const char* format_name)
+{
+    CV_Assert(width > 0 && nch > 0);
+
+    const size_t row_size = static_cast<size_t>(width) * static_cast<size_t>(nch);
+    if (row_size >= MAX_IMAGE_ROW_SIZE)
+        CV_Error(cv::Error::StsOutOfRange,
+                 cv::format("%s: row size exceeds maximum allowed size", format_name));
+
+    return validateToInt(row_size);
+}
+
 #define  SCALE  14
 #define  cR  (int)(0.299*(1 << SCALE) + 0.5)
 #define  cG  (int)(0.587*(1 << SCALE) + 0.5)
diff --git a/modules/imgcodecs/src/utils.hpp b/modules/imgcodecs/src/utils.hpp
index 8b0ad1a9e9..3ed18eaaba 100644
--- a/modules/imgcodecs/src/utils.hpp
+++ b/modules/imgcodecs/src/utils.hpp
@@ -135,6 +135,16 @@ uchar* FillGrayRow4( uchar* data, uchar* indices, int len, uchar* palette );
 uchar* FillColorRow1( uchar* data, uchar* indices, int len, PaletteEntry* palette );
 uchar* FillGrayRow1( uchar* data, uchar* indices, int len, uchar* palette );
 
+static const size_t MAX_IMAGE_ROW_SIZE = static_cast<size_t>(1) << 28;  // 256 MB
+
+struct RowPitchParams {
+    int src_pitch;
+    size_t bytes_per_row;
+};
+
+RowPitchParams calculateRowPitch(int width, int bpp, int alignment, const char* format_name);
+int calculateRowSize(int width, int nch, const char* format_name);
+
 CV_INLINE bool  isBigEndian( void )
 {
 #ifdef WORDS_BIGENDIAN