diff --git a/include/exiv2/value.hpp b/include/exiv2/value.hpp
index 64a8ca7..4e9f285 100644
--- a/include/exiv2/value.hpp
+++ b/include/exiv2/value.hpp
@@ -1658,11 +1658,13 @@ namespace Exiv2 {
         ok_ = true;
         return static_cast<long>(value_[n]);
     }
+// #55 crash when value_[n].first == LONG_MIN
+#define LARGE_INT 1000000
     // Specialization for rational
     template<>
     inline long ValueType<Rational>::toLong(long n) const
     {
-        ok_ = (value_[n].second != 0);
+        ok_ = (value_[n].second != 0 && -LARGE_INT < value_[n].first && value_[n].first < LARGE_INT);
         if (!ok_) return 0;
         return value_[n].first / value_[n].second;
     }
@@ -1670,7 +1672,7 @@ namespace Exiv2 {
     template<>
     inline long ValueType<URational>::toLong(long n) const
     {
-        ok_ = (value_[n].second != 0);
+        ok_ = (value_[n].second != 0 && value_[n].first < LARGE_INT);
         if (!ok_) return 0;
         return value_[n].first / value_[n].second;
     }
diff --git a/src/basicio.cpp b/src/basicio.cpp
index 95589cd..f2e1518 100644
--- a/src/basicio.cpp
+++ b/src/basicio.cpp
@@ -990,6 +990,7 @@ namespace Exiv2 {
     DataBuf FileIo::read(long rcount)
     {
         assert(p_->fp_ != 0);
+        if ( (size_t) rcount > size() ) throw Error(57);
         DataBuf buf(rcount);
         long readCount = read(buf.pData_, buf.size_);
         buf.size_ = readCount;
diff --git a/src/error.cpp b/src/error.cpp
index 80378c1..e90a9c0 100644
--- a/src/error.cpp
+++ b/src/error.cpp
@@ -106,6 +106,9 @@ namespace {
         { 52, N_("%1 has invalid XMP value type `%2'") }, // %1=key, %2=value type
         { 53, N_("Not a valid ICC Profile") },
         { 54, N_("Not valid XMP") },
+        { 55, N_("tiff directory length is too large") },
+        { 56, N_("invalid type value detected in Image::printIFDStructure") },
+        { 57, N_("invalid memory allocation request") },
     };
 
 }
diff --git a/src/image.cpp b/src/image.cpp
index 0d82804..ec5b873 100644
--- a/src/image.cpp
+++ b/src/image.cpp
@@ -399,7 +399,13 @@ namespace Exiv2 {
                                 ;
 
                 // if ( offset > io.size() ) offset = 0; // Denial of service?
-                DataBuf  buf(size*count + pad+20);  // allocate a buffer
+
+                // #55 memory allocation crash test/data/POC8
+                long long allocate = (long long) (size*count + pad+20);
+                if ( allocate > (long long) io.size() ) {
+                    throw Error(57);
+                }
+                DataBuf  buf(allocate);  // allocate a buffer
                 std::memcpy(buf.pData_,dir.pData_+8,4);  // copy dir[8:11] into buffer (short strings)
                 if ( count*size > 4 ) {            // read into buffer
                     size_t   restore = io.tell();  // save
diff --git a/test/bugfixes-test.sh b/test/bugfixes-test.sh
index f91c675..c90ae55 100755
--- a/test/bugfixes-test.sh
+++ b/test/bugfixes-test.sh
@@ -602,6 +602,7 @@ source ./functions.source
     runTest exiv2 -pX                   $filename | xmllint --format -
 
     num=1231
+    printf "$num " >&3
     for X in a b; do
       filename=exiv2-bug$num$X.jpg
       echo '------>' Bug $filename '<-------' >&2
@@ -622,6 +623,7 @@ source ./functions.source
     runTest exiv2 -pa                   $filename
 
     num=1252
+    printf "$num " >&3
     for X in a b; do
       filename=exiv2-bug$num$X.exv
       echo '------>' Bug $filename '<-------' >&2
@@ -629,6 +631,13 @@ source ./functions.source
       runTest exiv2 -pa --grep lens/i   $filename
     done
 
+    num=g55
+    printf "$num " >&3
+    filename=POC8
+    echo '------>' Bug $filename '<-------' >&2
+    copyTestFile                      $filename
+    runTest exiv2                     $filename 2>/dev/null
+
 ) 3>&1 > $results 2>&1
 
 printf "\n"
