diff --git a/CHANGES.md b/CHANGES.md
index 77324d1678..8c7bfb0cdd 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -1,4 +1,4 @@
-CHANGES - 2.3.0 - 2019-08-01
+CHANGES - 2.3.0 - 2019-08-07
 ============================
 
 
@@ -26,6 +26,8 @@ Changes in CUPS v2.3.0
   to a named group (Issue #5613)
 - Added USB quirks rule for HP LaserJet 1015 (Issue #5617)
 - Fixed some PPD parser issues (Issue #5623, Issue #5624)
+- The IPP parser no longer allows invalid member attributes in collections
+  (Issue #5630)
 - Fixed an issue with unsupported "sides" values in the IPP backend
   (rdar://51775322)
 - The scheduler would restart continuously when idle and printers were not
diff --git a/cups/ipp.c b/cups/ipp.c
index 0248cb9d29..6fae52a006 100644
--- a/cups/ipp.c
+++ b/cups/ipp.c
@@ -3040,8 +3040,13 @@ ippReadIO(void       *src,		/* I - Data source */
 
           DEBUG_printf(("2ippReadIO: name length=%d", n));
 
-          if (n == 0 && tag != IPP_TAG_MEMBERNAME &&
-	      tag != IPP_TAG_END_COLLECTION)
+          if (n && parent)
+          {
+            _cupsSetError(IPP_STATUS_ERROR_INTERNAL, _("Invalid named IPP attribute in collection."), 1);
+            DEBUG_puts("1ippReadIO: bad attribute name in collection.");
+            return (IPP_STATE_ERROR);
+          }
+          else if (n == 0 && tag != IPP_TAG_MEMBERNAME && tag != IPP_TAG_END_COLLECTION)
 	  {
 	   /*
 	    * More values for current attribute...
diff --git a/cups/testipp.c b/cups/testipp.c
index 67700c6423..aca52021a4 100644
--- a/cups/testipp.c
+++ b/cups/testipp.c
@@ -187,6 +187,71 @@ static ipp_uchar_t collection[] =	/* Collection buffer */
 		  0x00, 0x00,		/* No name */
 		  0x00, 0x00,		/* No value */
 
+		  IPP_TAG_END		/* end tag */
+		};
+static ipp_uchar_t bad_collection[] =	/* Collection buffer (bad encoding) */
+		{
+		  0x01, 0x01,		/* IPP version */
+		  0x00, 0x02,		/* Print-Job operation */
+		  0x00, 0x00, 0x00, 0x01,
+		  			/* Request ID */
+
+		  IPP_TAG_OPERATION,
+
+		  IPP_TAG_CHARSET,
+		  0x00, 0x12,		/* Name length + name */
+		  'a','t','t','r','i','b','u','t','e','s','-',
+		  'c','h','a','r','s','e','t',
+		  0x00, 0x05,		/* Value length + value */
+		  'u','t','f','-','8',
+
+		  IPP_TAG_LANGUAGE,
+		  0x00, 0x1b,		/* Name length + name */
+		  'a','t','t','r','i','b','u','t','e','s','-',
+		  'n','a','t','u','r','a','l','-','l','a','n',
+		  'g','u','a','g','e',
+		  0x00, 0x02,		/* Value length + value */
+		  'e','n',
+
+		  IPP_TAG_URI,
+		  0x00, 0x0b,		/* Name length + name */
+		  'p','r','i','n','t','e','r','-','u','r','i',
+		  0x00, 0x1c,			/* Value length + value */
+		  'i','p','p',':','/','/','l','o','c','a','l',
+		  'h','o','s','t','/','p','r','i','n','t','e',
+		  'r','s','/','f','o','o',
+
+		  IPP_TAG_JOB,		/* job group tag */
+
+		  IPP_TAG_BEGIN_COLLECTION,
+		  			/* begCollection tag */
+		  0x00, 0x09,		/* Name length + name */
+		  'm', 'e', 'd', 'i', 'a', '-', 'c', 'o', 'l',
+		  0x00, 0x00,		/* No value */
+		    IPP_TAG_BEGIN_COLLECTION,
+		    			/* begCollection tag */
+		    0x00, 0x0a,		/* Name length + name */
+		    'm', 'e', 'd', 'i', 'a', '-', 's', 'i', 'z', 'e',
+		    0x00, 0x00,		/* No value */
+		      IPP_TAG_INTEGER,	/* integer tag */
+		      0x00, 0x0b,	/* Name length + name */
+		      'x', '-', 'd', 'i', 'm', 'e', 'n', 's', 'i', 'o', 'n',
+		      0x00, 0x04,	/* Value length + value */
+		      0x00, 0x00, 0x54, 0x56,
+		      IPP_TAG_INTEGER,	/* integer tag */
+		      0x00, 0x0b,	/* Name length + name */
+		      'y', '-', 'd', 'i', 'm', 'e', 'n', 's', 'i', 'o', 'n',
+		      0x00, 0x04,	/* Value length + value */
+		      0x00, 0x00, 0x6d, 0x24,
+		    IPP_TAG_END_COLLECTION,
+		    			/* endCollection tag */
+		    0x00, 0x00,		/* No name */
+		    0x00, 0x00,		/* No value */
+		  IPP_TAG_END_COLLECTION,
+		  			/* endCollection tag */
+		  0x00, 0x00,		/* No name */
+		  0x00, 0x00,		/* No value */
+
 		  IPP_TAG_END		/* end tag */
 		};
 
@@ -586,12 +651,33 @@ main(int  argc,			/* I - Number of command-line arguments */
 
     ippDelete(request);
 
+   /*
+    * Read the bad collection data and confirm we get an error...
+    */
+
+    fputs("Read Bad Collection from Memory: ", stdout);
+
+    request = ippNew();
+    data.rpos    = 0;
+    data.wused   = sizeof(bad_collection);
+    data.wsize   = sizeof(bad_collection);
+    data.wbuffer = bad_collection;
+
+    while ((state = ippReadIO(&data, (ipp_iocb_t)read_cb, 1, NULL, request)) != IPP_STATE_DATA)
+      if (state == IPP_STATE_ERROR)
+	break;
+
+    if (state != IPP_STATE_ERROR)
+      puts("FAIL (read successful)");
+    else
+      puts("PASS");
+
    /*
     * Read the mixed data and confirm we converted everything to rangeOfInteger
     * values...
     */
 
-    printf("Read Mixed integer/rangeOfInteger from Memory: ");
+    fputs("Read Mixed integer/rangeOfInteger from Memory: ", stdout);
 
     request = ippNew();
     data.rpos    = 0;