diff --git a/changes/bug27316 b/changes/bug27316
new file mode 100644
index 0000000000..cec9348912
--- /dev/null
+++ b/changes/bug27316
@@ -0,0 +1,3 @@
+  o Minor bugfixes (protover):
+    - Reject protocol names containing bytes other than alphanumeric characters
+      and hyphens ([A-Za-z0-9-]). Fixes bug 27316; bugfix on 0.2.9.4-alpha.
diff --git a/src/or/protover.c b/src/or/protover.c
index 0e8902196d..c973660980 100644
--- a/src/or/protover.c
+++ b/src/or/protover.c
@@ -23,6 +23,7 @@
 
 #define PROTOVER_PRIVATE
 
+#include "compat.h"
 #include "or.h"
 #include "protover.h"
 #include "routerparse.h"
@@ -178,6 +179,16 @@ parse_version_range(const char *s, const char *end_of_range,
   return -1;
 }
 
+static int
+is_valid_keyword(const char *s, size_t n)
+{
+  for (size_t i = 0; i < n; i++) {
+    if (!TOR_ISALNUM(s[i]) && s[i] != '-')
+      return 0;
+  }
+  return 1;
+}
+
 /** Parse a single protocol entry from <b>s</b> up to an optional
  * <b>end_of_entry</b> pointer, and return that protocol entry. Return NULL
  * on error.
@@ -212,6 +223,11 @@ parse_single_entry(const char *s, const char *end_of_entry)
              MAX_PROTOCOL_NAME_LENGTH, escaped(out->name));
     goto error;
   }
+
+  /* The name must contain only alphanumeric characters and hyphens. */
+  if (!is_valid_keyword(s, equals-s))
+    goto error;
+
   out->name = tor_strndup(s, equals-s);
 
   tor_assert(equals < end_of_entry);
@@ -920,4 +936,3 @@ protover_free_all(void)
 }
 
 #endif /* !defined(HAVE_RUST) */
-
diff --git a/src/test/test_protover.c b/src/test/test_protover.c
index 15c5febe0b..2476693005 100644
--- a/src/test/test_protover.c
+++ b/src/test/test_protover.c
@@ -543,6 +543,10 @@ test_protover_vote_roundtrip(void *args)
     const char *input;
     const char *expected_output;
   } examples[] = {
+    { "Risqu\u00e9=1", NULL },
+    { ",,,=1", NULL },
+    { "\xc1=1", NULL },
+    { "Foo_Bar=1", NULL },
     { "Fkrkljdsf", NULL },
     { "Zn=4294967295", NULL },
     { "Zn=4294967295-1", NULL },