diff --git a/docs/en/docs/css/custom.css b/docs/en/docs/css/custom.css
index b88d694845..e207197c75 100644
--- a/docs/en/docs/css/custom.css
+++ b/docs/en/docs/css/custom.css
@@ -32,15 +32,16 @@
   display: none;
 }
 
-/* External links: absolute URLs opening in new tab
+/* External links: detected by JS comparing origin to site origin
+   JS sets data-external-link on links pointing outside the site
    Skip image links, .no-link-icon, and .announce-link */
-a[target="_blank"][href^="http"]:not(:has(img)):not(.no-link-icon):not(.announce-link) {
+a[data-external-link]:not(:has(img)):not(.no-link-icon):not(.announce-link) {
   /* For right to left languages */
   direction: ltr;
   display: inline-block;
 }
 
-a[target="_blank"][href^="http"]:not(:has(img)):not(.no-link-icon):not(.announce-link)::after {
+a[data-external-link]:not(:has(img)):not(.no-link-icon):not(.announce-link)::after {
   content: "";
   display: inline-block;
   width: 0.75em;
@@ -57,19 +58,20 @@ a[target="_blank"][href^="http"]:not(:has(img)):not(.no-link-icon):not(.announce
   mask-repeat: no-repeat;
 }
 
-a[target="_blank"][href^="http"]:not(:has(img)):not(.no-link-icon):not(.announce-link):hover::after {
+a[data-external-link]:not(:has(img)):not(.no-link-icon):not(.announce-link):hover::after {
   opacity: 0.85;
 }
 
-/* Internal links opening in new tab: relative URLs with target=_blank
+/* Internal links opening in new tab: same-origin links with target=_blank
+   JS sets data-internal-link on links pointing to the same site origin
    Skip image links, .no-link-icon, and .announce-link */
-a[target="_blank"]:not([href^="http"]):not(:has(img)):not(.no-link-icon):not(.announce-link) {
+a[data-internal-link][target="_blank"]:not(:has(img)):not(.no-link-icon):not(.announce-link) {
   /* For right to left languages */
   direction: ltr;
   display: inline-block;
 }
 
-a[target="_blank"]:not([href^="http"]):not(:has(img)):not(.no-link-icon):not(.announce-link)::after {
+a[data-internal-link][target="_blank"]:not(:has(img)):not(.no-link-icon):not(.announce-link)::after {
   content: "";
   display: inline-block;
   width: 0.75em;
@@ -86,7 +88,7 @@ a[target="_blank"]:not([href^="http"]):not(:has(img)):not(.no-link-icon):not(.an
   mask-repeat: no-repeat;
 }
 
-a[target="_blank"]:not([href^="http"]):not(:has(img)):not(.no-link-icon):not(.announce-link):hover::after {
+a[data-internal-link][target="_blank"]:not(:has(img)):not(.no-link-icon):not(.announce-link):hover::after {
   opacity: 0.85;
 }
 
diff --git a/docs/en/docs/js/custom.js b/docs/en/docs/js/custom.js
index be326d3029..311995d7cd 100644
--- a/docs/en/docs/js/custom.js
+++ b/docs/en/docs/js/custom.js
@@ -174,10 +174,38 @@ function handleSponsorImages() {
         });
 }
 
+function openLinksInNewTab() {
+    const siteUrl = document.querySelector("link[rel='canonical']")?.href
+        || window.location.origin;
+    const siteOrigin = new URL(siteUrl).origin;
+    document.querySelectorAll(".md-content a[href]").forEach(a => {
+        if (a.getAttribute("target") === "_self") return;
+        const href = a.getAttribute("href");
+        if (!href) return;
+        try {
+            const url = new URL(href, window.location.href);
+            // Skip same-page anchor links (only the hash differs)
+            if (url.origin === window.location.origin
+                && url.pathname === window.location.pathname
+                && url.search === window.location.search) return;
+            if (!a.hasAttribute("target")) {
+                a.setAttribute("target", "_blank");
+                a.setAttribute("rel", "noopener");
+            }
+            if (url.origin !== siteOrigin) {
+                a.dataset.externalLink = "";
+            } else {
+                a.dataset.internalLink = "";
+            }
+        } catch (_) {}
+    });
+}
+
 async function main() {
     setupTermynal();
     showRandomAnnouncement('announce-left', 5000)
     handleSponsorImages();
+    openLinksInNewTab();
 }
 document$.subscribe(() => {
     main()
diff --git a/docs/en/docs/release-notes.md b/docs/en/docs/release-notes.md
index c1af37912e..7a2b8d233b 100644
--- a/docs/en/docs/release-notes.md
+++ b/docs/en/docs/release-notes.md
@@ -16,6 +16,7 @@ hide:
 
 ### Internal
 
+* 🔨 Update script to autofix permalinks to account for headers with Markdown links. PR [#15062](https://github.com/fastapi/fastapi/pull/15062) by [@tiangolo](https://github.com/tiangolo).
 * 📌 Pin Click for MkDocs live reload. PR [#15057](https://github.com/fastapi/fastapi/pull/15057) by [@tiangolo](https://github.com/tiangolo).
 * ⬆ Bump werkzeug from 3.1.5 to 3.1.6. PR [#14948](https://github.com/fastapi/fastapi/pull/14948) by [@dependabot[bot]](https://github.com/apps/dependabot).
 * ⬆ Bump pydantic-ai from 1.62.0 to 1.63.0. PR [#15035](https://github.com/fastapi/fastapi/pull/15035) by [@dependabot[bot]](https://github.com/apps/dependabot).