Index: utils/ofzip/OFZIP.h
==================================================================
--- utils/ofzip/OFZIP.h
+++ utils/ofzip/OFZIP.h
@@ -18,10 +18,12 @@
 #import "OFObject.h"
 #import "OFString.h"
 
 #import "Archive.h"
 
+OF_ASSUME_NONNULL_BEGIN
+
 #ifndef S_IRWXG
 # define S_IRWXG 0
 #endif
 #ifndef S_IRWXO
 # define S_IRWXO 0
@@ -42,6 +44,9 @@
 - (bool)shouldExtractFile: (OFString *)fileName
 	      outFileName: (OFString *)outFileName;
 - (ssize_t)copyBlockFromStream: (OFStream *)input
 		      toStream: (OFStream *)output
 		      fileName: (OFString *)fileName;
+- (nullable OFString *)safeLocalPathForPath: (OFString *)path;
 @end
+
+OF_ASSUME_NONNULL_END

Index: utils/ofzip/OFZIP.m
==================================================================
--- utils/ofzip/OFZIP.m
+++ utils/ofzip/OFZIP.m
@@ -575,6 +575,52 @@
 		return -1;
 	}
 
 	return length;
 }
+
+- (OFString *)safeLocalPathForPath: (OFString *)path
+{
+	void *pool = objc_autoreleasePoolPush();
+
+	path = [path stringByStandardizingPath];
+
+#if defined(OF_WINDOWS) || defined(OF_MSDOS)
+	if ([path containsString: @":"] || [path hasPrefix: @"\\"]) {
+#elif defined(OF_AMIGAOS)
+	if ([path containsString: @":"] || [path hasPrefix: @"/"]) {
+#else
+	if ([path hasPrefix: @"/"]) {
+#endif
+		objc_autoreleasePoolPop(pool);
+		return nil;
+	}
+
+	if ([path length] == 0) {
+		objc_autoreleasePoolPop(pool);
+		return nil;
+	}
+
+	/*
+	 * After -[stringByStandardizingPath], everything representing parent
+	 * directory should be at the beginning, so in theory checking the
+	 * first component should be enough. But it does not hurt being
+	 * paranoid and checking all components, just in case.
+	 */
+	for (OFString *component in [path pathComponents]) {
+#ifdef OF_AMIGAOS
+		if ([component length] == 0 || [component isEqual: @"/"]) {
+#else
+		if ([component length] == 0 || [component isEqual: @".."]) {
+#endif
+			objc_autoreleasePoolPop(pool);
+			return nil;
+		}
+	}
+
+	[path retain];
+
+	objc_autoreleasePoolPop(pool);
+
+	return [path autorelease];
+}
 @end

Index: utils/ofzip/TarArchive.m
==================================================================
--- utils/ofzip/TarArchive.m
+++ utils/ofzip/TarArchive.m
@@ -253,13 +253,11 @@
 
 	while ((entry = [_archive nextEntry]) != nil) {
 		void *pool = objc_autoreleasePoolPush();
 		OFString *fileName = [entry fileName];
 		of_tar_archive_entry_type_t type = [entry type];
-		OFString *outFileName = [fileName stringByStandardizingPath];
-		OFArray OF_GENERIC(OFString *) *pathComponents;
-		OFString *directory;
+		OFString *outFileName, *directory;
 		OFFile *output;
 		OFStream *stream;
 		uint64_t written = 0, size = [entry size];
 		int8_t percent = -1, newPercent;
 
@@ -276,40 +274,21 @@
 			continue;
 		}
 
 		[missing removeObject: fileName];
 
-#if !defined(OF_WINDOWS) && !defined(OF_MSDOS)
-		if ([outFileName hasPrefix: @"/"]) {
-#else
-		if ([outFileName hasPrefix: @"/"] ||
-		    [outFileName containsString: @":"]) {
-#endif
+		outFileName = [app safeLocalPathForPath: fileName];
+		if (outFileName == nil) {
 			[of_stderr writeLine: OF_LOCALIZED(
 			    @"refusing_to_extract_file",
 			    @"Refusing to extract %[file]!",
 			    @"file", fileName)];
 
 			app->_exitStatus = 1;
 			goto outer_loop_end;
 		}
 
-		pathComponents = [outFileName pathComponents];
-		for (OFString *component in pathComponents) {
-			if ([component length] == 0 ||
-			    [component isEqual: @".."]) {
-				[of_stderr writeLine: OF_LOCALIZED(
-				    @"refusing_to_extract_file",
-				    @"Refusing to extract %[file]!",
-				    @"file", fileName)];
-
-				app->_exitStatus = 1;
-				goto outer_loop_end;
-			}
-		}
-		outFileName = [OFString pathWithComponents: pathComponents];
-
 		if (app->_outputLevel >= 0)
 			[of_stdout writeString: OF_LOCALIZED(@"extracting_file",
 			    @"Extracting %[file]...",
 			    @"file", fileName)];
 

Index: utils/ofzip/ZIPArchive.m
==================================================================
--- utils/ofzip/ZIPArchive.m
+++ utils/ofzip/ZIPArchive.m
@@ -205,13 +205,11 @@
 	    [OFMutableSet setWithArray: files];
 
 	for (OFZIPArchiveEntry *entry in [_archive entries]) {
 		void *pool = objc_autoreleasePoolPush();
 		OFString *fileName = [entry fileName];
-		OFString *outFileName = [fileName stringByStandardizingPath];
-		OFArray OF_GENERIC(OFString *) *pathComponents;
-		OFString *directory;
+		OFString *outFileName, *directory;
 		OFStream *stream;
 		OFFile *output;
 		uint64_t written = 0, size = [entry uncompressedSize];
 		int8_t percent = -1, newPercent;
 
@@ -218,40 +216,21 @@
 		if (!all && ![files containsObject: fileName])
 			continue;
 
 		[missing removeObject: fileName];
 
-#if !defined(OF_WINDOWS) && !defined(OF_MSDOS)
-		if ([outFileName hasPrefix: @"/"]) {
-#else
-		if ([outFileName hasPrefix: @"/"] ||
-		    [outFileName containsString: @":"]) {
-#endif
+		outFileName = [app safeLocalPathForPath: fileName];
+		if (outFileName == nil) {
 			[of_stderr writeLine: OF_LOCALIZED(
 			    @"refusing_to_extract_file",
 			    @"Refusing to extract %[file]!",
 			    @"file", fileName)];
 
 			app->_exitStatus = 1;
 			goto outer_loop_end;
 		}
 
-		pathComponents = [outFileName pathComponents];
-		for (OFString *component in pathComponents) {
-			if ([component length] == 0 ||
-			    [component isEqual: @".."]) {
-				[of_stderr writeLine: OF_LOCALIZED(
-				    @"refusing_to_extract_file",
-				    @"Refusing to extract %[file]!",
-				    @"file", fileName)];
-
-				app->_exitStatus = 1;
-				goto outer_loop_end;
-			}
-		}
-		outFileName = [OFString pathWithComponents: pathComponents];
-
 		if (app->_outputLevel >= 0)
 			[of_stdout writeString: OF_LOCALIZED(@"extracting_file",
 			    @"Extracting %[file]...",
 			    @"file", fileName)];