diff --git a/CHANGELOG.md b/CHANGELOG.md
index 92157762..533e6bdb 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 `cosign@latest` to 3.1.1.
+
 ## [2.81.9] - 2026-06-10
 
 - Update `wasm-bindgen@latest` to 0.2.123.
diff --git a/manifests/cosign.json b/manifests/cosign.json
index 189580ba..e2274f5c 100644
--- a/manifests/cosign.json
+++ b/manifests/cosign.json
@@ -27,10 +27,13 @@
     }
   },
   "latest": {
-    "version": "3.0.6"
+    "version": "3.1.1"
   },
   "3": {
-    "version": "3.0.6"
+    "version": "3.1.1"
+  },
+  "3.1": {
+    "version": "3.1.1"
   },
   "3.1.1": {
     "x86_64_linux_musl": {