diff --git a/src/dispatch_common.c b/src/dispatch_common.c
index 013027f..ba6fca3 100644
--- a/src/dispatch_common.c
+++ b/src/dispatch_common.c
@@ -347,6 +347,8 @@ epoxy_conservative_gl_version(void)
 bool
 epoxy_extension_in_string(const char *extension_list, const char *ext)
 {
+    if (!extension_list)
+        return false;
     const char *ptr = extension_list;
     int len = strlen(ext);