diff --git a/src/spellfile.c b/src/spellfile.c
index c7d87c6..8b1a3a6 100644
--- a/src/spellfile.c
+++ b/src/spellfile.c
@@ -1595,6 +1595,9 @@
     len = get4c(fd);
     if (len < 0)
 	return SP_TRUNCERROR;
+    if (len >= 0x3ffffff)
+	/* Invalid length, multiply with sizeof(int) would overflow. */
+	return SP_FORMERROR;
     if (len > 0)
     {
 	/* Allocate the byte array. */