diff --git a/src/campaigns/campaigns.controller.ts b/src/campaigns/campaigns.controller.ts
index 00b02e0..02e8bf5 100644
--- a/src/campaigns/campaigns.controller.ts
+++ b/src/campaigns/campaigns.controller.ts
@@ -83,7 +83,9 @@ export class CampaignsController {
       );
     }
 
-    return this.campaignsService.updateCampaign(req.user.id, id, body);
+    const userId = req.user?.sub as string;
+    const isAdmin = req.user?.role === 'ADMIN';
+    return this.campaignsService.updateCampaign(userId, id, body, isAdmin);
   }
 
   @Get()
diff --git a/src/campaigns/campaigns.service.spec.ts b/src/campaigns/campaigns.service.spec.ts
new file mode 100644
index 0000000..fb07554
--- /dev/null
+++ b/src/campaigns/campaigns.service.spec.ts
@@ -0,0 +1,105 @@
+import { Test, TestingModule } from '@nestjs/testing';
+import { ForbiddenException, NotFoundException } from '@nestjs/common';
+import { CampaignsService } from './campaigns.service';
+import { PrismaService } from '../prisma/prisma.service';
+import { StellarTransactionsService } from '../stellar/stellar-transactions.service';
+
+describe('CampaignsService.updateCampaign (access control)', () => {
+  let service: CampaignsService;
+  let prisma: {
+    campaign: { findUnique: jest.Mock; update: jest.Mock };
+    auditLog: { create: jest.Mock };
+  };
+
+  const OWNER_ID = 'wallet-b-user-id';
+  const ATTACKER_ID = 'wallet-a-user-id';
+  const CAMPAIGN_ID = '11111111-1111-1111-1111-111111111111';
+
+  const existingCampaign = {
+    id: CAMPAIGN_ID,
+    title: 'Original title',
+    description: 'Original description',
+    story: 'Original story',
+    imageUrl: 'https://cdn.example.com/original.png',
+    creatorId: OWNER_ID,
+  };
+
+  beforeEach(async () => {
+    prisma = {
+      campaign: {
+        findUnique: jest.fn().mockResolvedValue(existingCampaign),
+        update: jest
+          .fn()
+          .mockImplementation(({ data }) => ({ ...existingCampaign, ...data })),
+      },
+      auditLog: { create: jest.fn().mockResolvedValue({}) },
+    };
+
+    const module: TestingModule = await Test.createTestingModule({
+      providers: [
+        CampaignsService,
+        { provide: PrismaService, useValue: prisma },
+        { provide: StellarTransactionsService, useValue: {} },
+      ],
+    }).compile();
+
+    service = module.get<CampaignsService>(CampaignsService);
+  });
+
+  it('throws NotFoundException when the campaign does not exist', async () => {
+    prisma.campaign.findUnique.mockResolvedValueOnce(null);
+
+    await expect(
+      service.updateCampaign(OWNER_ID, CAMPAIGN_ID, { title: 'x' }),
+    ).rejects.toBeInstanceOf(NotFoundException);
+    expect(prisma.campaign.update).not.toHaveBeenCalled();
+  });
+
+  it('rejects a non-owner, non-admin caller with 403 (IDOR regression)', async () => {
+    await expect(
+      service.updateCampaign(ATTACKER_ID, CAMPAIGN_ID, { title: 'Defaced' }),
+    ).rejects.toBeInstanceOf(ForbiddenException);
+    expect(prisma.campaign.update).not.toHaveBeenCalled();
+    expect(prisma.auditLog.create).not.toHaveBeenCalled();
+  });
+
+  it('rejects a non-owner attempting to inject an imageUrl with 403 (phishing regression)', async () => {
+    await expect(
+      service.updateCampaign(ATTACKER_ID, CAMPAIGN_ID, {
+        coverImageUrl: 'https://phishing.example.com/steal.png',
+      }),
+    ).rejects.toBeInstanceOf(ForbiddenException);
+    expect(prisma.campaign.update).not.toHaveBeenCalled();
+  });
+
+  it('allows the campaign owner to update and writes an audit log', async () => {
+    const result = await service.updateCampaign(OWNER_ID, CAMPAIGN_ID, {
+      title: 'Updated by owner',
+    });
+
+    expect(result.title).toBe('Updated by owner');
+    expect(prisma.campaign.update).toHaveBeenCalledTimes(1);
+    expect(prisma.auditLog.create).toHaveBeenCalledWith(
+      expect.objectContaining({
+        data: expect.objectContaining({
+          userId: OWNER_ID,
+          action: 'CAMPAIGN_UPDATED',
+          resourceType: 'campaign',
+          resourceId: CAMPAIGN_ID,
+        }),
+      }),
+    );
+  });
+
+  it('allows an admin override even when they are not the owner', async () => {
+    const result = await service.updateCampaign(
+      ATTACKER_ID,
+      CAMPAIGN_ID,
+      { title: 'Updated by admin' },
+      true,
+    );
+
+    expect(result.title).toBe('Updated by admin');
+    expect(prisma.campaign.update).toHaveBeenCalledTimes(1);
+  });
+});
diff --git a/src/campaigns/campaigns.service.ts b/src/campaigns/campaigns.service.ts
index 473f8e7..51de190 100644
--- a/src/campaigns/campaigns.service.ts
+++ b/src/campaigns/campaigns.service.ts
@@ -62,10 +62,16 @@ export class CampaignsService {
     });
   }
 
+  /**
+   * Update campaign metadata. Only the campaign creator or an admin may update.
+   * Enforces per-resource ownership to prevent IDOR (OWASP A01:2021) and writes
+   * an AuditLog row for every successful update.
+   */
   async updateCampaign(
     userId: string,
     campaignId: string,
     dto: UpdateCampaignDto,
+    isAdmin = false,
   ) {
     const campaign = await this.prisma.campaign.findUnique({
       where: { id: campaignId },
@@ -75,7 +81,11 @@ export class CampaignsService {
       throw new NotFoundException('Campaign not found');
     }
 
-    return this.prisma.campaign.update({
+    if (campaign.creatorId !== userId && !isAdmin) {
+      throw new ForbiddenException('Not authorized to update this campaign');
+    }
+
+    const updated = await this.prisma.campaign.update({
       where: { id: campaignId },
       data: {
         title: dto.title ?? campaign.title,
@@ -84,6 +94,26 @@ export class CampaignsService {
         imageUrl: dto.coverImageUrl ?? campaign.imageUrl,
       },
     });
+
+    await this.prisma.auditLog.create({
+      data: {
+        userId,
+        action: 'CAMPAIGN_UPDATED',
+        resourceType: 'campaign',
+        resourceId: campaignId,
+        details: JSON.stringify({
+          isAdmin,
+          changes: {
+            title: dto.title,
+            description: dto.description,
+            story: dto.story,
+            coverImageUrl: dto.coverImageUrl,
+          },
+        }),
+      },
+    });
+
+    return updated;
   }
 
   /**