diff -rup a/crypt.c b/crypt.c
--- a/crypt.c	2007-01-05 07:47:36.000000000 -0800
+++ b/crypt.c	2016-11-30 13:13:47.569570000 -0800
@@ -465,7 +465,17 @@ int decrypt(__G__ passwrd)
     GLOBAL(pInfo->encrypted) = FALSE;
     defer_leftover_input(__G);
     for (n = 0; n < RAND_HEAD_LEN; n++) {
-        b = NEXTBYTE;
+        /* 2012-11-23 SMS.  (OUSPG report.)
+        * Quit early if compressed size < HEAD_LEN.  The resulting
+        * error message ("unable to get password") could be improved,
+        * but it's better than trying to read nonexistent data, and
+        * then continuing with a negative G.csize.  (See
+        * fileio.c:readbyte()).
+        */
+        if ((b = NEXTBYTE) == (ush)EOF)
+        {
+           return PK_ERR;
+        }
         h[n] = (uch)b;
         Trace((stdout, " (%02x)", h[n]));
     }
diff -rup a/extract.c b/extract.c
--- a/extract.c	2009-03-13 18:32:52.000000000 -0700
+++ b/extract.c	2016-11-30 13:23:26.163704000 -0800
@@ -1255,8 +1255,17 @@ static int extract_or_test_entrylist(__G
         if (G.lrec.compression_method == STORED) {
             zusz_t csiz_decrypted = G.lrec.csize;
 
-            if (G.pInfo->encrypted)
+            if (G.pInfo->encrypted) {
+                if (csiz_decrypted <= 12) {
+                    /* handle the error now to prevent unsigned overflow */
+                    Info(slide, 0x401, ((char *)slide,
+                         LoadFarStringSmall(ErrUnzipNoFile),
+                         LoadFarString(InvalidComprData),
+                         LoadFarStringSmall2(Inflate)));
+                         return PK_ERR;
+                }
                 csiz_decrypted -= 12;
+            }
             if (G.lrec.ucsize != csiz_decrypted) {
                 Info(slide, 0x401, ((char *)slide,
                   LoadFarStringSmall2(WrnStorUCSizCSizDiff),
@@ -2701,6 +2710,12 @@ __GDEF
     int repeated_buf_err;
     bz_stream bstrm;
 
+    if (G.incnt <= 0 && G.csize <= 0L) {
+        /* avoid an infinite loop */
+        Trace((stderr, "UZbunzip2() got empty input\n"));
+        return 2;
+    }
+
 #if (defined(DLL) && !defined(NO_SLIDE_REDIR))
     if (G.redirect_slide)
         wsize = G.redirect_size, redirSlide = G.redirect_buffer;