kc3-lang/md4c

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 23b521a..6524a72 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -9,7 +9,10 @@ Fixes:
  * Fixed some quadratic behaviors:
    [#58](https://github.com/mity/md4c/issues/58),
    [#59](https://github.com/mity/md4c/issues/59),
-   [#60](https://github.com/mity/md4c/issues/60)
+   [#60](https://github.com/mity/md4c/issues/60),
+   [#66](https://github.com/mity/md4c/issues/66)
+
+   Thanks to Anders Kaseorg for finding all those issues.
 
  * [#61](https://github.com/mity/md4c/issues/59): Flag `MD_FLAG_NOHTMLSPANS`
    erroneously affected also recognition of CommonMark autolinks.
diff --git a/md4c/md4c.c b/md4c/md4c.c
index fc5a72a..d1ad2ea 100644
--- a/md4c/md4c.c
+++ b/md4c/md4c.c
@@ -4799,7 +4799,7 @@ abort:
  ***********************/
 
 static int
-md_is_hr_line(MD_CTX* ctx, OFF beg, OFF* p_end)
+md_is_hr_line(MD_CTX* ctx, OFF beg, OFF* p_end, OFF* p_killer)
 {
     OFF off = beg + 1;
     int n = 1;
@@ -4810,12 +4810,16 @@ md_is_hr_line(MD_CTX* ctx, OFF beg, OFF* p_end)
         off++;
     }
 
-    if(n < 3)
+    if(n < 3) {
+        *p_killer = off;
         return FALSE;
+    }
 
     /* Nothing else can be present on the line. */
-    if(off < ctx->size  &&  !ISNEWLINE(off))
+    if(off < ctx->size  &&  !ISNEWLINE(off)) {
+        *p_killer = off;
         return FALSE;
+    }
 
     *p_end = off;
     return TRUE;
@@ -5395,6 +5399,7 @@ md_analyze_line(MD_CTX* ctx, OFF beg, OFF* p_end,
     MD_CONTAINER container = { 0 };
     int prev_line_has_list_loosening_effect = ctx->last_line_has_list_loosening_effect;
     OFF off = beg;
+    OFF hr_killer = 0;
     int ret = 0;
 
     line->indent = md_line_indentation(ctx, total_indent, off, &off);
@@ -5570,8 +5575,8 @@ redo:
     }
 
     /* Check for thematic break line. */
-    if(line->indent < ctx->code_indent_offset  &&  ISANYOF(off, _T("-_*"))) {
-        if(md_is_hr_line(ctx, off, &off)) {
+    if(line->indent < ctx->code_indent_offset  &&  ISANYOF(off, _T("-_*"))  &&  off >= hr_killer) {
+        if(md_is_hr_line(ctx, off, &off, &hr_killer)) {
             line->type = MD_LINE_HR;
             goto done;
         }
diff --git a/test/pathological_tests.py b/test/pathological_tests.py
index 2d7c700..71fcaff 100755
--- a/test/pathological_tests.py
+++ b/test/pathological_tests.py
@@ -77,7 +77,10 @@ pathological = {
                   re.compile("(``){50000}")),
     "many broken link titles":
                  (("[ (](" * 50000),
-                  re.compile("(\[ \(\]\(){50000}"))
+                  re.compile("(\[ \(\]\(){50000}")),
+    "broken thematic break":
+                 (("* " * 50000 + "a"),
+                  re.compile("<ul>\r?\n(<li><ul>\r?\n){49999}<li>a</li>\r?\n</ul>\r?\n(</li>\r?\n</ul>\r?\n){49999}"))
     }
 
 whitespace_re = re.compile('/s+/')