diff --git a/lib/legacy/zstd_v05.c b/lib/legacy/zstd_v05.c
index 6425ad2cc..42e925c42 100644
--- a/lib/legacy/zstd_v05.c
+++ b/lib/legacy/zstd_v05.c
@@ -2885,8 +2885,7 @@ size_t HUFv05_decompress (void* dst, size_t dstSize, const void* cSrc, size_t cS
 
     /* validation checks */
     if (dstSize == 0) return ERROR(dstSize_tooSmall);
-    if (cSrcSize > dstSize) return ERROR(corruption_detected);   /* invalid */
-    if (cSrcSize == dstSize) { memcpy(dst, cSrc, dstSize); return dstSize; }   /* not compressed */
+    if (cSrcSize >= dstSize) return ERROR(corruption_detected);   /* invalid, or not compressed, but not compressed already dealt with */
     if (cSrcSize == 1) { memset(dst, *(const BYTE*)cSrc, dstSize); return dstSize; }   /* RLE */
 
     /* decoder timing evaluation */