diff --git a/apps/mcp/lib/tools/submissions/create.ts b/apps/mcp/lib/tools/submissions/create.ts
index c55ec5a..92b9e40 100644
--- a/apps/mcp/lib/tools/submissions/create.ts
+++ b/apps/mcp/lib/tools/submissions/create.ts
@@ -142,6 +142,7 @@ export async function handleSubmissionsCreate(raw: unknown) {
     prUrl: parsed.data.pr_url,
     expectedGithubHandle: auth.profile.github_handle,
     expectedRepoUrl: repoUrl,
+    expectedIssueUrl: b.github_issue_url,
     token: process.env.GITHUB_TOKEN,
   });
   if (!verify.ok) {
diff --git a/packages/shared/src/github/verify-pr-ownership.ts b/packages/shared/src/github/verify-pr-ownership.ts
index f61d0ac..f1dec8d 100644
--- a/packages/shared/src/github/verify-pr-ownership.ts
+++ b/packages/shared/src/github/verify-pr-ownership.ts
@@ -12,6 +12,8 @@ export type VerifyPrOwnershipInput = {
   expectedGithubHandle: string;
   /** Full URL like `https://github.com/owner/repo` (no trailing slash). */
   expectedRepoUrl: string;
+  /** Optional full URL like `https://github.com/owner/repo/issues/123`. */
+  expectedIssueUrl?: string | null;
   /** Optional GitHub token for higher rate limit. */
   token?: string;
 };
@@ -24,6 +26,7 @@ export type VerifyPrOwnershipResult =
         | "pr_not_found"
         | "author_mismatch"
         | "repo_mismatch"
+        | "issue_mismatch"
         | "rate_limited"
         | "invalid_url"
         | "upstream_error";
@@ -32,6 +35,12 @@ export type VerifyPrOwnershipResult =
 const PR_URL_RE =
   /^https:\/\/github\.com\/([^/]+)\/([^/]+)\/pull\/(\d+)\/?$/;
 
+const ISSUE_URL_RE =
+  /^https:\/\/github\.com\/([^/]+)\/([^/]+)\/issues\/(\d+)\/?$/;
+
+const CLOSING_KEYWORD_RE =
+  /(?:close[sd]?|fix(?:e[sd])?|resolve[sd]?)\s+(?:(?:https:\/\/github\.com\/([^/]+)\/([^/]+)\/issues\/)?#?(\d+))/gi;
+
 export async function verifyPrOwnership(
   input: VerifyPrOwnershipInput
 ): Promise<VerifyPrOwnershipResult> {
@@ -62,7 +71,11 @@ export async function verifyPrOwnership(
 
   if (!res.ok) return { ok: false, reason: "upstream_error" };
 
-  let body: { user: { login: string } | null; base: { repo: { html_url: string } | null } | null };
+  let body: {
+    user: { login: string } | null;
+    base: { repo: { html_url: string } | null } | null;
+    body?: string | null;
+  };
   try {
     body = (await res.json()) as typeof body;
   } catch {
@@ -84,5 +97,41 @@ export async function verifyPrOwnership(
     return { ok: false, reason: "repo_mismatch" };
   }
 
+  if (input.expectedIssueUrl) {
+    const expectedIssue = parseIssueUrl(input.expectedIssueUrl);
+    if (!expectedIssue) return { ok: false, reason: "issue_mismatch" };
+
+    if (!prBodyClosesIssue(body.body ?? "", expectedIssue)) {
+      return { ok: false, reason: "issue_mismatch" };
+    }
+  }
+
   return { ok: true };
 }
+
+function parseIssueUrl(url: string): { owner: string; repo: string; number: string } | null {
+  const m = url.match(ISSUE_URL_RE);
+  if (!m) return null;
+  return { owner: m[1]!.toLowerCase(), repo: m[2]!.toLowerCase(), number: m[3]! };
+}
+
+function prBodyClosesIssue(
+  body: string,
+  expectedIssue: { owner: string; repo: string; number: string }
+): boolean {
+  for (const m of body.matchAll(CLOSING_KEYWORD_RE)) {
+    const [, owner, repo, number] = m;
+    if (number !== expectedIssue.number) continue;
+
+    // `Fixes #123` is scoped to the already-verified base repo. A fully
+    // qualified URL must point to the same repo as the bounty issue.
+    if (!owner && !repo) return true;
+    if (
+      owner?.toLowerCase() === expectedIssue.owner &&
+      repo?.toLowerCase() === expectedIssue.repo
+    ) {
+      return true;
+    }
+  }
+  return false;
+}
diff --git a/packages/shared/tests/github/verify-pr-ownership.test.ts b/packages/shared/tests/github/verify-pr-ownership.test.ts
index e36f87a..b01d08b 100644
--- a/packages/shared/tests/github/verify-pr-ownership.test.ts
+++ b/packages/shared/tests/github/verify-pr-ownership.test.ts
@@ -33,6 +33,50 @@ describe("verifyPrOwnership", () => {
     expect(result).toEqual({ ok: true });
   });
 
+  it("returns ok when the PR body closes the expected issue", async () => {
+    fetchMock.mockResolvedValueOnce(
+      new Response(
+        JSON.stringify({
+          user: { login: "alice" },
+          base: { repo: { html_url: "https://github.com/acme/proj" } },
+          body: "Implements the fix.\n\nCloses #67",
+        }),
+        { status: 200 }
+      )
+    );
+
+    const result = await verifyPrOwnership({
+      prUrl: "https://github.com/acme/proj/pull/42",
+      expectedGithubHandle: "alice",
+      expectedRepoUrl: "https://github.com/acme/proj",
+      expectedIssueUrl: "https://github.com/acme/proj/issues/67",
+    });
+
+    expect(result).toEqual({ ok: true });
+  });
+
+  it("returns issue_mismatch when the PR body closes a different issue", async () => {
+    fetchMock.mockResolvedValueOnce(
+      new Response(
+        JSON.stringify({
+          user: { login: "alice" },
+          base: { repo: { html_url: "https://github.com/acme/proj" } },
+          body: "This solves the diff-filter bug.\n\nCloses #67",
+        }),
+        { status: 200 }
+      )
+    );
+
+    const result = await verifyPrOwnership({
+      prUrl: "https://github.com/acme/proj/pull/42",
+      expectedGithubHandle: "alice",
+      expectedRepoUrl: "https://github.com/acme/proj",
+      expectedIssueUrl: "https://github.com/acme/proj/issues/70",
+    });
+
+    expect(result).toEqual({ ok: false, reason: "issue_mismatch" });
+  });
+
   it("returns author_mismatch when login differs", async () => {
     fetchMock.mockResolvedValueOnce(
       new Response(
diff --git a/relayer/src/submission-handler.ts b/relayer/src/submission-handler.ts
index f9a96b8..296b6ec 100644
--- a/relayer/src/submission-handler.ts
+++ b/relayer/src/submission-handler.ts
@@ -727,6 +727,7 @@ async function checkPrOwnership(
       prUrl: sub.prUrl,
       expectedGithubHandle: ownershipCtx.githubHandle,
       expectedRepoUrl: bountyRepoUrl,
+      expectedIssueUrl: ownershipCtx.githubIssueUrl,
       token: deps.githubToken ?? undefined,
     });
   } catch (err) {