Index: src/OFDate.m
==================================================================
--- src/OFDate.m
+++ src/OFDate.m
@@ -268,17 +268,18 @@
 	      format: (OFString*)format
 {
 	self = [super init];
 
 	@try {
+		const char *UTF8String = [string UTF8String];
 		struct tm tm = { 0 };
 		int16_t tz = 0;
 
 		tm.tm_isdst = -1;
 
-		if (of_strptime([string UTF8String], [format UTF8String],
-		    &tm, &tz) == NULL)
+		if (of_strptime(UTF8String, [format UTF8String],
+		    &tm, &tz) != UTF8String + [string UTF8StringLength])
 			@throw [OFInvalidFormatException exception];
 
 		_seconds = tmAndTzToTime(&tm, &tz);
 	} @catch (id e) {
 		[self release];
@@ -292,10 +293,11 @@
 		   format: (OFString*)format
 {
 	self = [super init];
 
 	@try {
+		const char *UTF8String = [string UTF8String];
 		struct tm tm = { 0 };
 		/*
 		 * of_strptime() can never set this to INT16_MAX, no matter
 		 * what is passed to it, so this is a safe way to figure out if
 		 * the date contains a time zone.
@@ -302,12 +304,12 @@
 		 */
 		int16_t tz = INT16_MAX;
 
 		tm.tm_isdst = -1;
 
-		if (of_strptime([string UTF8String], [format UTF8String],
-		    &tm, &tz) == NULL)
+		if (of_strptime(UTF8String, [format UTF8String],
+		    &tm, &tz) != UTF8String + [string UTF8StringLength])
 			@throw [OFInvalidFormatException exception];
 
 		if (tz == INT16_MAX) {
 #ifndef OF_WINDOWS
 			if ((_seconds = mktime(&tm)) == -1)

Index: tests/OFDateTests.m
==================================================================
--- tests/OFDateTests.m
+++ tests/OFDateTests.m
@@ -20,10 +20,12 @@
 
 #import "OFDate.h"
 #import "OFString.h"
 #import "OFAutoreleasePool.h"
 
+#import "OFInvalidFormatException.h"
+
 #import "of_strptime.h"
 
 #import "TestsAppDelegate.h"
 
 static OFString *module = @"OFDate";
@@ -55,18 +57,28 @@
 	TEST(@"+[dateWithDateString:format:]",
 	    [[[OFDate dateWithDateString: @"2000-06-20T12:34:56+0200"
 				  format: @"%Y-%m-%dT%H:%M:%S%z"] description]
 	    isEqual: @"2000-06-20T10:34:56Z"]);
 
+	EXPECT_EXCEPTION(@"Detection of unparsed in "
+	    @"+[dateWithDateString:format:]", OFInvalidFormatException,
+	    [OFDate dateWithDateString: @"2000-06-20T12:34:56+0200x"
+				format: @"%Y-%m-%dT%H:%M:%S%z"])
+
 	/*
 	 * We can only test local dates that specify a time zone, as the local
 	 * time zone differs between systems.
 	 */
 	TEST(@"+[dateWithLocalDateString:format:]",
 	    [[[OFDate dateWithLocalDateString: @"2000-06-20T12:34:56-0200"
 				       format: @"%Y-%m-%dT%H:%M:%S%z"]
 	    description] isEqual: @"2000-06-20T14:34:56Z"]);
+
+	EXPECT_EXCEPTION(@"Detection of unparsed in "
+	    @"+[dateWithLocalDateString:format:]", OFInvalidFormatException,
+	    [OFDate dateWithLocalDateString: @"2000-06-20T12:34:56+0200x"
+				     format: @"%Y-%m-%dT%H:%M:%S%z"])
 
 	TEST(@"-[isEqual:]",
 	    [d1 isEqual: [OFDate dateWithTimeIntervalSince1970: 0]] &&
 	    ![d1 isEqual: [OFDate dateWithTimeIntervalSince1970: 0.0000001]])