diff --git a/changes/ticket40286_minimal b/changes/ticket40286_minimal
new file mode 100644
index 0000000000..b8669debaa
--- /dev/null
+++ b/changes/ticket40286_minimal
@@ -0,0 +1,5 @@
+  o Major bugfixes (denial of service):
+    - Disable the dump_desc() function that we used to dump unparseable
+      information to disk. It was called incorrectly in several places,
+      in a way that could lead to excessive CPU usage.
+      Fixes bug 40286; bugfix on 0.2.2.1-alpha.
diff --git a/src/feature/dirparse/unparseable.c b/src/feature/dirparse/unparseable.c
index 98b68f90bb..da3c80e383 100644
--- a/src/feature/dirparse/unparseable.c
+++ b/src/feature/dirparse/unparseable.c
@@ -497,6 +497,12 @@ dump_desc,(const char *desc, const char *type))
 {
   tor_assert(desc);
   tor_assert(type);
+#ifndef TOR_UNIT_TESTS
+  /* On older versions of Tor we are disabling this function, since it
+   * can be called with strings that are far too long. */
+  if (1)
+    return;
+#endif
   size_t len;
   /* The SHA256 of the string */
   uint8_t digest_sha256[DIGEST256_LEN];