diff --git a/src/lib/services/report-render.service.ts b/src/lib/services/report-render.service.ts
index 1b2f8c81..026aae79 100644
--- a/src/lib/services/report-render.service.ts
+++ b/src/lib/services/report-render.service.ts
@@ -30,7 +30,7 @@ import { getStorageBackend } from '@/lib/storage';
 import { resolvePortLogo } from '@/lib/pdf/brand-kit/logo';
 import { renderPdf } from '@/lib/pdf/render';
 import { sendEmail } from '@/lib/email';
-import { updateReportRunStatus } from '@/lib/services/report-runs.service';
+import { updateReportRunStatus, userCanAccessPort } from '@/lib/services/report-runs.service';
 import { CodedError, NotFoundError } from '@/lib/errors';
 import {
   fetchActivityData,
@@ -221,15 +221,39 @@ export async function renderReportRun(reportRunId: string): Promise<ReportRun> {
     }
 
     // P7: optional cover-brand swap. When config.coverBrandPortId points
-    // at a port the rep has access to, the cover-page logo + port name
-    // come from THAT port's brand kit instead of the report's source
-    // port. Useful for cross-port leadership decks; falls back to the
-    // source port when the override port is missing / inaccessible.
+    // at a port the triggering user has access to, the cover-page logo +
+    // port name come from THAT port's brand kit instead of the report's
+    // source port. Useful for cross-port leadership decks; falls back to
+    // the source port when the override port is missing / inaccessible.
+    //
+    // H11 defense-in-depth: enqueue-time validation (createReportRun)
+    // already rejects forbidden overrides, but a stale/forged config row
+    // could still reach the worker. Only honour the override when it equals
+    // the run's own port OR the triggering user is a member of that port
+    // (super-admins included via userCanAccessPort). Otherwise silently
+    // fall back to the source port's branding — a forged config can never
+    // leak a foreign tenant's logo/name onto the rendered PDF.
     const params = (run.config as Record<string, unknown>) ?? {};
-    const overrideBrandPortId =
+    const requestedBrandPortId =
       typeof params.coverBrandPortId === 'string' && params.coverBrandPortId.length > 0
         ? params.coverBrandPortId
         : null;
+    const overrideAllowed =
+      requestedBrandPortId !== null &&
+      (requestedBrandPortId === run.portId ||
+        (await userCanAccessPort(run.triggeredByUserId, requestedBrandPortId)));
+    if (requestedBrandPortId !== null && !overrideAllowed) {
+      logger.warn(
+        {
+          reportRunId: run.id,
+          runPortId: run.portId,
+          requestedBrandPortId,
+          triggeredByUserId: run.triggeredByUserId,
+        },
+        'Ignoring cover-brand override: triggering user is not a member of the requested port (H11)',
+      );
+    }
+    const overrideBrandPortId = overrideAllowed ? requestedBrandPortId : null;
     const brandPortId = overrideBrandPortId ?? run.portId;
     const brandPort =
       overrideBrandPortId === null
diff --git a/src/lib/services/report-runs.service.ts b/src/lib/services/report-runs.service.ts
index 831c8fb3..867190b8 100644
--- a/src/lib/services/report-runs.service.ts
+++ b/src/lib/services/report-runs.service.ts
@@ -22,8 +22,9 @@ import {
   type ReportRun,
   type NewReportRun,
 } from '@/lib/db/schema/reports';
+import { userPortRoles, userProfiles } from '@/lib/db/schema/users';
 import { createAuditLog, type AuditMeta } from '@/lib/audit';
-import { NotFoundError, ValidationError } from '@/lib/errors';
+import { ForbiddenError, NotFoundError, ValidationError } from '@/lib/errors';
 import type {
   CreateReportRunInput,
   ListReportRunsInput,
@@ -36,6 +37,31 @@ export interface ListReportRunsResult {
   hasMore: boolean;
 }
 
+/**
+ * True when the user may act on behalf of `portId`: either a platform
+ * super-admin, or the holder of a `userPortRoles` membership row for that
+ * port. Mirrors the Socket.IO `userCanAccessPort` guard — the canonical
+ * "is this user a member of this tenant" check. Used to gate the
+ * cover-brand override so a rep can't stamp a foreign port's logo +
+ * name onto a report (audit finding H11). Empty/falsy userId → false.
+ */
+export async function userCanAccessPort(
+  userId: string | null | undefined,
+  portId: string,
+): Promise<boolean> {
+  if (!userId) return false;
+  const profile = await db.query.userProfiles.findFirst({
+    where: eq(userProfiles.userId, userId),
+    columns: { isSuperAdmin: true },
+  });
+  if (profile?.isSuperAdmin) return true;
+  const role = await db.query.userPortRoles.findFirst({
+    where: and(eq(userPortRoles.userId, userId), eq(userPortRoles.portId, portId)),
+    columns: { id: true },
+  });
+  return Boolean(role);
+}
+
 export async function listReportRuns(
   portId: string,
   query: ListReportRunsInput,
@@ -98,6 +124,31 @@ export async function createReportRun(
     throw new ValidationError(`config.kind must equal "${input.kind}"`);
   }
 
+  // H11: the cover-brand override (`config.coverBrandPortId`) swaps the
+  // cover-page logo + port name to another port's brand kit. All report
+  // DATA still comes from `options.portId`, so the override's only effect
+  // is rendering a foreign port's branding — a cross-tenant leak vector.
+  //
+  // For USER-triggered runs there is an accountable user, so gate the
+  // override to ports that user belongs to (super-admins exempt) and reject
+  // before the row is even queued. For SCHEDULE-triggered runs there is no
+  // human actor to attribute access to, so we don't reject here (that would
+  // silently kill a whole scheduled report); the renderer's defense-in-depth
+  // check strips an unauthorized override and falls back to the source
+  // port's branding instead.
+  const coverBrandPortId = (input.config as { coverBrandPortId?: unknown }).coverBrandPortId;
+  if (
+    options.triggeredBy === 'user' &&
+    typeof coverBrandPortId === 'string' &&
+    coverBrandPortId.length > 0 &&
+    coverBrandPortId !== options.portId
+  ) {
+    const allowed = await userCanAccessPort(options.triggeredByUserId, coverBrandPortId);
+    if (!allowed) {
+      throw new ForbiddenError('You do not have access to the port selected for cover branding');
+    }
+  }
+
   // Verify template ownership when provided. Belt-and-braces: the route
   // already gates by port via withAuth, but a stale template id from a
   // cached UI would otherwise produce an opaque FK constraint error.
diff --git a/src/lib/validators/reports.ts b/src/lib/validators/reports.ts
index 2c1dbb3d..ac2a5329 100644
--- a/src/lib/validators/reports.ts
+++ b/src/lib/validators/reports.ts
@@ -72,7 +72,12 @@ export const createReportRunSchema = z.object({
   kind: z.enum(REPORT_KINDS),
   templateId: z.string().optional(),
   // Same opaque shape report_templates accepts — the render queue
-  // re-validates per-kind at use time.
+  // re-validates per-kind at use time. NOTE: the optional
+  // `config.coverBrandPortId` (cover-page brand swap) is intentionally NOT
+  // shape-validated here — it requires a runtime per-user membership check
+  // that Zod can't express. `createReportRun` rejects an override the
+  // triggering user can't access (H11), and the renderer strips a
+  // stale/forged one as defense-in-depth.
   config: z.record(z.string(), z.unknown()),
   outputFormat: z.enum(REPORT_OUTPUT_FORMATS).default('pdf'),
   emailTo: z.array(recipientSchema).max(50).optional(),