diff --git a/ChangeLog b/ChangeLog
index f39c52c3..649e5aac 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,10 @@
 2017-07-26  Jay Berkenbilt  <ejb@ql.org>
 
+	* Detect infinite loops while resolving objects. This could happen
+	if something inside an object that had to be resolved during
+	parsing, such as a stream length, recursively referenced the
+	object being resolved.
+
 	* CVE-2017-9208: Handle references to and appearance of object 0
 	as a special case. Object 0 is not allowed, and qpdf was using it
 	internally to represent direct objects.
diff --git a/include/qpdf/QPDF.hh b/include/qpdf/QPDF.hh
index f7a31edf..4742275f 100644
--- a/include/qpdf/QPDF.hh
+++ b/include/qpdf/QPDF.hh
@@ -603,6 +603,25 @@ class QPDF
         int gen;
     };
 
+    class ResolveRecorder
+    {
+      public:
+        ResolveRecorder(QPDF* qpdf, QPDFObjGen const& og) :
+            qpdf(qpdf),
+            og(og)
+        {
+            qpdf->resolving.insert(og);
+        }
+        virtual ~ResolveRecorder()
+        {
+            this->qpdf->resolving.erase(og);
+        }
+      private:
+        QPDF* qpdf;
+        QPDFObjGen og;
+    };
+    friend class ResolveRecorder;
+
     void parse(char const* password);
     void warn(QPDFExc const& e);
     void setTrailer(QPDFObjectHandle obj);
@@ -1065,6 +1084,7 @@ class QPDF
     std::map<QPDFObjGen, QPDFXRefEntry> xref_table;
     std::set<int> deleted_objects;
     std::map<QPDFObjGen, ObjCache> obj_cache;
+    std::set<QPDFObjGen> resolving;
     QPDFObjectHandle trailer;
     std::vector<QPDFObjectHandle> all_pages;
     std::map<QPDFObjGen, int> pageobj_to_pages_pos;
diff --git a/libqpdf/QPDF.cc b/libqpdf/QPDF.cc
index 846f188f..ecc13491 100644
--- a/libqpdf/QPDF.cc
+++ b/libqpdf/QPDF.cc
@@ -1471,6 +1471,21 @@ QPDF::resolve(int objid, int generation)
     // to insert things into the object cache that don't actually
     // exist in the file.
     QPDFObjGen og(objid, generation);
+    if (this->resolving.count(og))
+    {
+        // This can happen if an object references itself directly or
+        // indirectly in some key that has to be resolved during
+        // object parsing, such as stream length.
+	QTC::TC("qpdf", "QPDF recursion loop in resolve");
+	warn(QPDFExc(qpdf_e_damaged_pdf, this->file->getName(),
+		     "", this->file->getLastOffset(),
+		     "loop detected resolving object " +
+		     QUtil::int_to_string(objid) + " " +
+		     QUtil::int_to_string(generation)));
+        return new QPDF_Null;
+    }
+    ResolveRecorder rr(this, og);
+
     if (! this->obj_cache.count(og))
     {
 	if (! this->xref_table.count(og))
diff --git a/qpdf/qpdf.testcov b/qpdf/qpdf.testcov
index f3ddd60d..8144d2c3 100644
--- a/qpdf/qpdf.testcov
+++ b/qpdf/qpdf.testcov
@@ -276,3 +276,4 @@ qpdf-c called qpdf_set_deterministic_ID 0
 QPDFObjectHandle indirect with 0 objid 0
 QPDF object id 0 0
 QPDF caught recursive xref reconstruction 0
+QPDF recursion loop in resolve 0
diff --git a/qpdf/qtest/qpdf.test b/qpdf/qtest/qpdf.test
index c45215fa..c0207019 100644
--- a/qpdf/qtest/qpdf.test
+++ b/qpdf/qtest/qpdf.test
@@ -206,7 +206,7 @@ $td->runtest("remove page we don't have",
 show_ntests();
 # ----------
 $td->notify("--- Miscellaneous Tests ---");
-$n_tests += 81;
+$n_tests += 82;
 
 $td->runtest("qpdf version",
 	     {$td->COMMAND => "qpdf --version"},
@@ -220,6 +220,7 @@ $td->runtest("C API: qpdf version",
 
 # Files to reproduce various bugs
 foreach my $d (
+    ["51", "resolve loop"],
     ["99", "object 0"],
     ["99b", "object 0"],
     ["100","xref reconstruction loop"],
diff --git a/qpdf/qtest/qpdf/issue-51.out b/qpdf/qtest/qpdf/issue-51.out
new file mode 100644
index 00000000..7f2192f6
--- /dev/null
+++ b/qpdf/qtest/qpdf/issue-51.out
@@ -0,0 +1,6 @@
+WARNING: issue-51.pdf: reported number of objects (0) inconsistent with actual number of objects (9)
+WARNING: issue-51.pdf (object 7 0, file position 553): expected endobj
+WARNING: issue-51.pdf (object 1 0, file position 359): expected endobj
+WARNING: issue-51.pdf (file position 70): loop detected resolving object 2 0
+WARNING: issue-51.pdf (object 2 0, file position 71): attempting to recover stream length
+issue-51.pdf (object 2 0, file position 71): unable to recover stream data
diff --git a/qpdf/qtest/qpdf/issue-51.pdf b/qpdf/qtest/qpdf/issue-51.pdf
new file mode 100644
index 00000000..2dafce1a
--- /dev/null
+++ b/qpdf/qtest/qpdf/issue-51.pdf
@@ -0,0 +1,22 @@
+%PDF-100000000000002 0 obj
+<</Length 2 0 R/000000/00000000000>>
+stream
+000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000001 0 obj
+<</0000000000000000 0 0 R/000000000 0 0 R/00000000[00000000000]/00000<</0/00000000000000000000000000000000>>/00000000 2 0 R>>000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000007 0 obj
+<</0000/0000000/00000 0 0 R
+/0000000000[1 0 R 0000 null null 0]
+/0000(00000)
+>>0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000xref
+0 9
+0000000000 00000 f 
+0000000200 00000 n 
+0000000009 00000 n 
+0000000000 00000 n 
+0000000000 00000 n 
+0000000000 00000 n 
+0000000000 00000 n 
+0000000400 00000 n 
+0000000000 00000 n 
+trailer<</Size 0/Root 7 0 R>>startxref
+740
+%%EOF
\ No newline at end of file