diff --git a/CHANGELOG.md b/CHANGELOG.md
index 1d7b131449..345ff4963b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,7 +4,7 @@ See the [releases page](https://github.com/github/codeql-action/releases) for th
 
 ## [UNRELEASED]
 
-No user facing changes.
+- Update default CodeQL bundle version to [2.25.6](https://github.com/github/codeql-action/releases/tag/codeql-bundle-v2.25.6). [#3948](https://github.com/github/codeql-action/pull/3948)
 
 ## 4.36.1 - 02 Jun 2026
 
diff --git a/lib/defaults.json b/lib/defaults.json
index a57ede64b9..7c82ff2a6e 100644
--- a/lib/defaults.json
+++ b/lib/defaults.json
@@ -1,6 +1,6 @@
 {
-  "bundleVersion": "codeql-bundle-v2.25.5",
-  "cliVersion": "2.25.5",
-  "priorBundleVersion": "codeql-bundle-v2.25.4",
-  "priorCliVersion": "2.25.4"
+  "bundleVersion": "codeql-bundle-v2.25.6",
+  "cliVersion": "2.25.6",
+  "priorBundleVersion": "codeql-bundle-v2.25.5",
+  "priorCliVersion": "2.25.5"
 }
diff --git a/lib/entry-points.js b/lib/entry-points.js
index c7edf0c1ec..c34a09bd3f 100644
--- a/lib/entry-points.js
+++ b/lib/entry-points.js
@@ -148959,8 +148959,8 @@ function wrapApiConfigurationError(e) {
 }
 
 // src/defaults.json
-var bundleVersion = "codeql-bundle-v2.25.5";
-var cliVersion = "2.25.5";
+var bundleVersion = "codeql-bundle-v2.25.6";
+var cliVersion = "2.25.6";
 
 // src/overlay/index.ts
 var fs4 = __toESM(require("fs"));
diff --git a/src/defaults.json b/src/defaults.json
index a57ede64b9..7c82ff2a6e 100644
--- a/src/defaults.json
+++ b/src/defaults.json
@@ -1,6 +1,6 @@
 {
-  "bundleVersion": "codeql-bundle-v2.25.5",
-  "cliVersion": "2.25.5",
-  "priorBundleVersion": "codeql-bundle-v2.25.4",
-  "priorCliVersion": "2.25.4"
+  "bundleVersion": "codeql-bundle-v2.25.6",
+  "cliVersion": "2.25.6",
+  "priorBundleVersion": "codeql-bundle-v2.25.5",
+  "priorCliVersion": "2.25.5"
 }