diff --git a/src/actions-util.ts b/src/actions-util.ts
index 38daf99c7..f6ee5c168 100644
--- a/src/actions-util.ts
+++ b/src/actions-util.ts
@@ -109,7 +109,7 @@ export const getCommitOid = async function (
 export const determineMergeBaseCommitOid = async function (): Promise<
   string | undefined
 > {
-  if (process.env.GITHUB_EVENT_NAME !== "pull_request") {
+  if (workflowEventName() !== "pull_request") {
     return undefined;
   }
 
@@ -821,9 +821,21 @@ export async function sendStatusReport<S extends StatusReportBase>(
   }
 }
 
+export function workflowEventName() {
+  // If the original event is dynamic CODESCANNING_EVENT_NAME will contain the right info (push/pull_request)
+  if (process.env["GITHUB_EVENT_NAME"] === "dynamic") {
+    const value = process.env["CODESCANNING_EVENT_NAME"];
+    if (value === undefined || value.length === 0) {
+      return process.env["GITHUB_EVENT_NAME"];
+    }
+    return value
+  }
+  return process.env["GITHUB_EVENT_NAME"];
+}
+
 // Was the workflow run triggered by a `push` event, for example as opposed to a `pull_request` event.
 function workflowIsTriggeredByPushEvent() {
-  return process.env["GITHUB_EVENT_NAME"] === "push";
+  return workflowEventName() === "push";
 }
 
 // Is dependabot the actor that triggered the current workflow run.
diff --git a/src/trap-caching.ts b/src/trap-caching.ts
index d5ae7d0da..295319788 100644
--- a/src/trap-caching.ts
+++ b/src/trap-caching.ts
@@ -91,7 +91,7 @@ export async function downloadTrapCaches(
   let baseSha = "unknown";
   const eventPath = process.env.GITHUB_EVENT_PATH;
   if (
-    process.env.GITHUB_EVENT_NAME === "pull_request" &&
+    actionsUtil.workflowEventName() === "pull_request" &&
     eventPath !== undefined
   ) {
     const event = JSON.parse(fs.readFileSync(path.resolve(eventPath), "utf-8"));
diff --git a/src/upload-lib.ts b/src/upload-lib.ts
index 5b483da9a..114b3d507 100644
--- a/src/upload-lib.ts
+++ b/src/upload-lib.ts
@@ -325,7 +325,7 @@ export function buildPayload(
       gitHubVersion.type !== util.GitHubVariant.GHES ||
       semver.satisfies(gitHubVersion.version, `>=3.1`)
     ) {
-      if (process.env.GITHUB_EVENT_NAME === "pull_request") {
+      if (actionsUtil.workflowEventName() === "pull_request") {
         if (
           commitOid === util.getRequiredEnvParam("GITHUB_SHA") &&
           mergeBaseCommitOid