diff --git a/tests/fsck/fsck_test.go b/tests/fsck/fsck_test.go
index cebc86ba..b70fd49e 100644
--- a/tests/fsck/fsck_test.go
+++ b/tests/fsck/fsck_test.go
@@ -49,6 +49,17 @@ func TestBrokenFsV14(t *testing.T) {
 	}
 }
 
+func TestMalleableBase64(t *testing.T) {
+	cmd := exec.Command(test_helpers.GocryptfsBinary, "-fsck", "-extpass", "echo test", "malleable_base64")
+	outBin, err := cmd.CombinedOutput()
+	out := string(outBin)
+	t.Log(out)
+	code := test_helpers.ExtractCmdExitCode(err)
+	if code != exitcodes.FsckErrors {
+		t.Errorf("wrong exit code, have=%d want=%d", code, exitcodes.FsckErrors)
+	}
+}
+
 func TestExampleFses(t *testing.T) {
 	dirfd, err := os.Open("../example_filesystems")
 	if err != nil {
diff --git "a/tests/fsck/malleable_base64/27AG8t-XZH7G9ou2OSD_z\ng" "b/tests/fsck/malleable_base64/27AG8t-XZH7G9ou2OSD_z\ng"
new file mode 100644
index 00000000..e69de29b
diff --git "a/tests/fsck/malleable_base64/27AG8t-XZH7G9ou2OSD_z\rg" "b/tests/fsck/malleable_base64/27AG8t-XZH7G9ou2OSD_z\rg"
new file mode 100644
index 00000000..e69de29b
diff --git a/tests/fsck/malleable_base64/27AG8t-XZH7G9ou2OSD_zg b/tests/fsck/malleable_base64/27AG8t-XZH7G9ou2OSD_zg
new file mode 100644
index 00000000..e69de29b
diff --git a/tests/fsck/malleable_base64/27AG8t-XZH7G9ou2OSD_zh b/tests/fsck/malleable_base64/27AG8t-XZH7G9ou2OSD_zh
new file mode 100644
index 00000000..e69de29b
diff --git a/tests/fsck/malleable_base64/gocryptfs.conf b/tests/fsck/malleable_base64/gocryptfs.conf
new file mode 100644
index 00000000..60987560
--- /dev/null
+++ b/tests/fsck/malleable_base64/gocryptfs.conf
@@ -0,0 +1,20 @@
+{
+	"Creator": "gocryptfs v2.4.0-dirty",
+	"EncryptedKey": "3RHFBE1hurYP6D4VsdqhQb3Bd/kd3vYsZohgpc2lDhwIM8lsk8FHOgZEtfG2HfEFsV374B6rktbXmrBBiperqw==",
+	"ScryptObject": {
+		"Salt": "9pQrdZWjpp1cTjuWNB/SqcLw+HOYeOTECga2yIpjjUU=",
+		"N": 1024,
+		"R": 8,
+		"P": 1,
+		"KeyLen": 32
+	},
+	"Version": 2,
+	"FeatureFlags": [
+		"HKDF",
+		"GCMIV128",
+		"DirIV",
+		"EMENames",
+		"LongNames",
+		"Raw64"
+	]
+}
diff --git a/tests/fsck/malleable_base64/gocryptfs.diriv b/tests/fsck/malleable_base64/gocryptfs.diriv
new file mode 100644
index 00000000..d8a6e22c
--- /dev/null
+++ b/tests/fsck/malleable_base64/gocryptfs.diriv
@@ -0,0 +1 @@
+cTh{½ÚEfDbúüÕ«Û
\ No newline at end of file