diff --git a/CHANGELOG.txt b/CHANGELOG.txt
index 254142d..e883aca 100644
--- a/CHANGELOG.txt
+++ b/CHANGELOG.txt
@@ -2,6 +2,8 @@
  * CHANGELOG.
  */
 
+05052007 - Fixed zip archiver: could do bogus seek if a small, non-zip file
+           got put through isArchive().
 04292007 - Minor const correctness tweak in zip archiver.
 04032007 - Added a "make dist" target for packing up source code releases.
            Reverted Unix recursive mutex code. There were some portability
diff --git a/archivers/zip.c b/archivers/zip.c
index 4f1a38d..da4f3a5 100644
--- a/archivers/zip.c
+++ b/archivers/zip.c
@@ -447,6 +447,8 @@ static PHYSFS_sint64 zip_find_end_of_central_dir(void *in, PHYSFS_sint64 *len)
             break;
 
         filepos -= (maxread - 4);
+        if (filepos < 0)
+            filepos = 0;
     } /* while */
 
     BAIL_IF_MACRO(!found, ERR_NOT_AN_ARCHIVE, -1);