diff --git a/src/node/markdown/markdown.ts b/src/node/markdown/markdown.ts
index 7ffe1e6d..c067e52a 100644
--- a/src/node/markdown/markdown.ts
+++ b/src/node/markdown/markdown.ts
@@ -510,6 +510,10 @@ export async function createMarkdownRenderer(
   if (options.component !== false) {
     componentPlugin(md, normalizePluginOptions(options.component))
   }
+  // pass an empty options object to gray-matter, otherwise it would memoize
+  // the results in an unbounded cache, where the key is the full file content.
+  // https://github.com/jonschlinkert/gray-matter/blob/310f9349381775d10a221cef903989eb5acc8843/index.js#L44-L47
+  ;(options.frontmatter ??= {}).grayMatterOptions ??= {}
   frontmatterPlugin(md, options.frontmatter)
   if (options.headers) {
     headersPlugin(md, {
diff --git a/src/node/utils/processIncludes.ts b/src/node/utils/processIncludes.ts
index afc86b1a..08e02d32 100644
--- a/src/node/utils/processIncludes.ts
+++ b/src/node/utils/processIncludes.ts
@@ -53,7 +53,7 @@ export function processIncludes(
         // region not found, it might be a header
         const headerContent =
           path.extname(includePath) === '.md'
-            ? matter(content).content
+            ? matter(content, {}).content
             : content
         const headerLines = headerContent.split(/\r?\n/)
         const tokens = md
@@ -95,7 +95,7 @@ export function processIncludes(
     }
 
     if (!hasMeta && path.extname(includePath) === '.md') {
-      content = matter(content).content
+      content = matter(content, {}).content
     }
 
     includes.push(slash(includePath))