diff --git a/autotests/kerfuffle/data/wget-download.tar.gz.1 b/autotests/kerfuffle/data/wget-download.tar.gz.1
new file mode 100644
index 0000000000000000000000000000000000000000..0000000000000000000000000000000000000000
GIT binary patch
literal 0
Hc$@<O00001

literal 0
Hc$@<O00001

diff --git a/autotests/kerfuffle/mimetypetest.cpp b/autotests/kerfuffle/mimetypetest.cpp
--- a/autotests/kerfuffle/mimetypetest.cpp
+++ b/autotests/kerfuffle/mimetypetest.cpp
@@ -70,6 +70,7 @@
     QTest::newRow("zip with wrong extension") << QFINDTESTDATA("data/zip_with_wrong_extension.rar") << QStringLiteral("application/zip");
     QTest::newRow("tar with special char in the extension") << QStringLiteral("foo.tar~1.gz") << compressedGzipTarMime;
     QTest::newRow("another tar with special char in the extension") << QStringLiteral("foo.ta4r.gz") << compressedGzipTarMime;
+    QTest::newRow("tar downloaded by wget") << QFINDTESTDATA("data/wget-download.tar.gz.1") << compressedGzipTarMime;
 
     // This ISO file may be detected-by-content as text/plain. See https://bugs.freedesktop.org/show_bug.cgi?id=80877
     QTest::newRow("archlinux truncated ISO") << QFINDTESTDATA("data/archlinux-2015.09.01-dual_truncated.iso") << isoMimeType;
diff --git a/kerfuffle/mimetypes.cpp b/kerfuffle/mimetypes.cpp
--- a/kerfuffle/mimetypes.cpp
+++ b/kerfuffle/mimetypes.cpp
@@ -48,7 +48,11 @@
     // we cannot rely on it when the archive extension is wrong; we need to validate by hand.
     if (fileinfo.completeSuffix().toLower().remove(QRegularExpression(QStringLiteral("[^a-z\\.]"))).contains(QStringLiteral("tar."))) {
         inputFile.chop(fileinfo.completeSuffix().length());
-        inputFile += fileinfo.completeSuffix().remove(QRegularExpression(QStringLiteral("[^a-zA-Z\\.]")));
+        QString cleanExtension = fileinfo.completeSuffix().toLower().remove(QRegularExpression(QStringLiteral("[^a-z\\.]")));
+        if (cleanExtension.endsWith(QLatin1Char('.'))) {
+            cleanExtension.chop(1);
+        }
+        inputFile += cleanExtension;
         qCDebug(ARK) << "Validated filename of compressed tar" << filename << "into filename" << inputFile;
     }