diff --git a/scripts/check-node-version-policy.mjs b/scripts/check-node-version-policy.mjs
index cceb9c7519..41f1dcce00 100644
--- a/scripts/check-node-version-policy.mjs
+++ b/scripts/check-node-version-policy.mjs
@@ -1,6 +1,7 @@
 import fs from "node:fs";
 import path from "node:path";
 import { fileURLToPath } from "node:url";
+import { isNode24ImageTag } from "./node-image-policy.mjs";
 
 const repoRoot = path.resolve(path.dirname(fileURLToPath(import.meta.url)), "..");
 const expectedEngine = ">=24.11.0";
@@ -48,7 +49,7 @@ walk(repoRoot, (filePath) => {
   if (!path.basename(filePath).startsWith("Dockerfile")) return;
   const source = fs.readFileSync(filePath, "utf8");
   for (const match of source.matchAll(/^\s*FROM\s+node:([^\s]+)/gm)) {
-    if (!match[1].startsWith("24-")) failures.push(`${relative(filePath)}: Node base image must use the Node 24 major, found node:${match[1]}`);
+    if (!isNode24ImageTag(match[1])) failures.push(`${relative(filePath)}: Node base image must use the Node 24 major, found node:${match[1]}`);
   }
   for (const match of source.matchAll(/^\s*ARG\s+NODE_(?:MAJOR|VERSION)=([^\s]+)/gm)) {
     if (match[1] !== "24") failures.push(`${relative(filePath)}: Node build argument must be 24, found ${match[1]}`);
diff --git a/scripts/node-image-policy.mjs b/scripts/node-image-policy.mjs
new file mode 100644
index 0000000000..318302ad2d
--- /dev/null
+++ b/scripts/node-image-policy.mjs
@@ -0,0 +1,5 @@
+// Accept the existing major tags and exact patch pins, with a required image variant.
+// A digest, when present, must be a complete SHA-256 pin.
+export function isNode24ImageTag(tag) {
+  return /^24(?:\.(?:0|[1-9]\d*)\.(?:0|[1-9]\d*))?-[a-z0-9][a-z0-9._-]*(?:@sha256:[a-f0-9]{64})?$/.test(tag);
+}
diff --git a/scripts/standard-image-contract.test.mjs b/scripts/standard-image-contract.test.mjs
index c903e95664..32e7677371 100644
--- a/scripts/standard-image-contract.test.mjs
+++ b/scripts/standard-image-contract.test.mjs
@@ -2,6 +2,23 @@ import assert from "node:assert/strict";
 import { createHash } from "node:crypto";
 import test from "node:test";
 import { standardImageDigest, resolveStandardImageDigest } from "./standard-image-contract.mjs";
+import { isNode24ImageTag } from "./node-image-policy.mjs";
+
+test("Node image policy accepts Node 24 major tags and exact security pins", () => {
+  for (const tag of ["24-trixie-slim", "24-bookworm-slim", "24-alpine3.23", "24.21.0-bookworm",
+    `24.21.0-bookworm@sha256:${"a".repeat(64)}`, `24-bookworm@sha256:${"0".repeat(64)}`]) {
+    assert.equal(isNode24ImageTag(tag), true, tag);
+  }
+});
+
+test("Node image policy rejects other majors, partial versions and malformed pins", () => {
+  for (const tag of ["240-bookworm", "25.21.0-bookworm", "v24.21.0-bookworm", "latest",
+    "24.21-bookworm", "24.21.0", "24.21.0-", "24..21.0-bookworm", "24.021.0-bookworm",
+    "24.21.0-bookworm@sha256:short", `24.21.0-bookworm@@sha256:${"a".repeat(64)}`,
+    `24.21.0-bookworm@sha256:${"a".repeat(64)}junk`, "${NODE_VERSION}-bookworm", "24-$(whoami)"]) {
+    assert.equal(isNode24ImageTag(tag), false, tag);
+  }
+});
 const descriptor = architecture => ({ platform: { os: "linux", architecture }, digest: `sha256:${"a".repeat(64)}`, size: 100 });
 const index = manifests => Buffer.from(JSON.stringify({ schemaVersion: 2, mediaType: "application/vnd.oci.image.index.v1+json", manifests }));
 test("signs the exact registry bytes, including both supported platforms", () => {