diff --git a/CHANGELOG.md b/CHANGELOG.md
index 98884f4b..875e84c5 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -10,6 +10,8 @@ Note: In this file, do not use the hard wrap in the middle of a sentence for com
 
 ## [Unreleased]
 
+- Update `zizmor@latest` to 1.21.0.
+
 - Update `syft@latest` to 1.40.1.
 
 - Update `uv@latest` to 0.9.26.
diff --git a/manifests/zizmor.json b/manifests/zizmor.json
index 630c34f0..22c6c021 100644
--- a/manifests/zizmor.json
+++ b/manifests/zizmor.json
@@ -19,10 +19,35 @@
   },
   "license_markdown": "[MIT](https://github.com/zizmorcore/zizmor/blob/main/LICENSE)",
   "latest": {
-    "version": "1.20.0"
+    "version": "1.21.0"
   },
   "1": {
-    "version": "1.20.0"
+    "version": "1.21.0"
+  },
+  "1.21": {
+    "version": "1.21.0"
+  },
+  "1.21.0": {
+    "x86_64_linux_gnu": {
+      "etag": "0x8DE54B70A8F6FD2",
+      "checksum": "23ad2dc14b87820abdfe0d8f2be189cc7bfb55ba8278ebce0d7a54220a7955d2"
+    },
+    "x86_64_macos": {
+      "etag": "0x8DE54B70A92C777",
+      "checksum": "c71d7f95c648cb6110cd7457a658aa3c6518ce5c9c18b2a423da6b87140513a1"
+    },
+    "x86_64_windows": {
+      "etag": "0x8DE54B70A8C183A",
+      "checksum": "978cfab35e719d91b88966f0964d3a5e86e37ee3aa67ef7c3ed8e29b11886499"
+    },
+    "aarch64_linux_gnu": {
+      "etag": "0x8DE54B70A977D1A",
+      "checksum": "05ce818c6028c3f7dbe8c4ed8b264d9f3edfc03d9be725aa2982f40779fbe183"
+    },
+    "aarch64_macos": {
+      "etag": "0x8DE54B70A8B7CA8",
+      "checksum": "a1ca0e0b885e9eae616bc5b5ede7836e9328266b67da59b3defcee01c2a3011a"
+    }
   },
   "1.20": {
     "version": "1.20.0"