diff --git a/.jules/sentinel.md b/.jules/sentinel.md
index 7902c442..46eeec21 100644
--- a/.jules/sentinel.md
+++ b/.jules/sentinel.md
@@ -30,3 +30,8 @@
 **Vulnerability:** Known high-severity vulnerabilities discovered by the audit in `js-yaml` and `nanoid` packages.
 **Learning:** Deeply nested dependencies (`js-yaml` via `eslint`, `nanoid` via `vitest/vite`) may expose the application to DoS or logic loops.
 **Prevention:** Use `pnpm.overrides` in the root `package.json` to enforce patched versions across all transitive paths in a pnpm workspace.
+
+## 2025-02-18 - [Fix CSV Formula Injection]
+**Vulnerability:** CSV exports generated user-controlled fields without escaping leading formula characters (e.g., `=`, `+`, `-`, `@`), enabling CSV Macro Injection.
+**Learning:** When exporting user-generated content to CSV, any string starting with spreadsheet formula characters can execute arbitrary commands or leak data when opened in tools like Excel.
+**Prevention:** Prepend a single quote (`'`) to non-numeric strings that start with `=, +, -, @` (including full-width equivalents and those preceded by whitespace) when serializing CSV fields.
diff --git a/packages/web/src/app/api/orgs/[orgSlug]/dashboard/sessions/route.ts b/packages/web/src/app/api/orgs/[orgSlug]/dashboard/sessions/route.ts
index 7d6a4d4a..b486b75b 100644
--- a/packages/web/src/app/api/orgs/[orgSlug]/dashboard/sessions/route.ts
+++ b/packages/web/src/app/api/orgs/[orgSlug]/dashboard/sessions/route.ts
@@ -1,18 +1,18 @@
-import { NextRequest, NextResponse } from 'next/server'
-import type { PaginatedResult, SessionItem } from '@argos/shared'
-import { Prisma } from '@prisma/client'
-import { db } from '@/lib/server/db'
-import { requireAuth } from '@/lib/server/auth-helper'
-import { handleRouteError } from '@/lib/server/error-helper'
-import { parseDateRange, parsePagination } from '@/lib/server/dashboard'
+import { NextRequest, NextResponse } from "next/server";
+import type { PaginatedResult, SessionItem } from "@argos/shared";
+import { Prisma } from "@prisma/client";
+import { db } from "@/lib/server/db";
+import { requireAuth } from "@/lib/server/auth-helper";
+import { handleRouteError } from "@/lib/server/error-helper";
+import { parseDateRange, parsePagination } from "@/lib/server/dashboard";
 import {
   assertOrgAccessBySlugOrResponse,
   resolveOrgScopedProjectIds,
-} from '@/lib/server/dashboard-route-helper'
-import { canAccessIndividualData, forbiddenByRole } from '@/lib/server/rbac'
+} from "@/lib/server/dashboard-route-helper";
+import { canAccessIndividualData, forbiddenByRole } from "@/lib/server/rbac";
 
-export const runtime = 'nodejs'
-export const dynamic = 'force-dynamic'
+export const runtime = "nodejs";
+export const dynamic = "force-dynamic";
 
 const sessionInclude = {
   user: { select: { id: true, name: true } },
@@ -22,34 +22,37 @@ const sessionInclude = {
   },
   // Title fallback — 저장된 title이 없는 세션용으로 첫 HUMAN 메시지 1건만 로딩
   messages: {
-    where: { role: 'HUMAN' as const },
-    orderBy: [{ timestamp: 'asc' as const }, { sequence: 'asc' as const }],
+    where: { role: "HUMAN" as const },
+    orderBy: [{ timestamp: "asc" as const }, { sequence: "asc" as const }],
     take: 1,
     select: { content: true },
   },
   _count: { select: { events: true } },
-} satisfies Prisma.ClaudeSessionInclude
+} satisfies Prisma.ClaudeSessionInclude;
 
-type SessionWithInclude = Prisma.ClaudeSessionGetPayload<{ include: typeof sessionInclude }>
+type SessionWithInclude = Prisma.ClaudeSessionGetPayload<{
+  include: typeof sessionInclude;
+}>;
 
 function getSessionTotals(session: SessionWithInclude) {
-  let inputTokens = 0
-  let outputTokens = 0
-  let estimatedCostUsd = 0
+  let inputTokens = 0;
+  let outputTokens = 0;
+  let estimatedCostUsd = 0;
 
   for (const r of session.usageRecords) {
-    inputTokens += r.inputTokens
-    outputTokens += r.outputTokens
-    estimatedCostUsd += r.estimatedCostUsd ?? 0
+    inputTokens += r.inputTokens;
+    outputTokens += r.outputTokens;
+    estimatedCostUsd += r.estimatedCostUsd ?? 0;
   }
 
-  return { inputTokens, outputTokens, estimatedCostUsd }
+  return { inputTokens, outputTokens, estimatedCostUsd };
 }
 
 function mapSessionItem(session: SessionWithInclude): SessionItem {
-  const totals = getSessionTotals(session)
-  const fallbackTitle = session.messages[0]?.content.slice(0, 200).trim() || null
-  const title = session.title?.trim() || fallbackTitle
+  const totals = getSessionTotals(session);
+  const fallbackTitle =
+    session.messages[0]?.content.slice(0, 200).trim() || null;
+  const title = session.title?.trim() || fallbackTitle;
 
   return {
     id: session.id,
@@ -68,113 +71,136 @@ function mapSessionItem(session: SessionWithInclude): SessionItem {
       slug: session.project.slug,
       name: session.project.name,
     },
-  }
+  };
 }
 
 function csvField(value: string | number | null | undefined) {
-  if (value === null || value === undefined) return ''
-  const text = String(value)
-  return /[",\r\n]/.test(text) ? `"${text.replaceAll('"', '""')}"` : text
+  if (value === null || value === undefined) return "";
+  let text = String(value);
+
+  // Prevent CSV Formula Injection (Spreadsheet Macro Injection)
+  if (typeof value !== "number") {
+    if (/^\s*[=+\-@\t\r\n＝＋－＠]/.test(text)) {
+      text = "'" + text;
+    }
+  }
+
+  return /[",\r\n]/.test(text) ? `"${text.replaceAll('"', '""')}"` : text;
 }
 
 function buildSessionsCsv(sessions: SessionWithInclude[]) {
   const headers = [
-    'Session ID',
-    'User',
-    'Project',
-    'Title',
-    'First Prompt',
-    'Input Tokens',
-    'Output Tokens',
-    'Estimated Cost USD',
-    'Event Count',
-    'Started At',
-    'Ended At',
-  ]
+    "Session ID",
+    "User",
+    "Project",
+    "Title",
+    "First Prompt",
+    "Input Tokens",
+    "Output Tokens",
+    "Estimated Cost USD",
+    "Event Count",
+    "Started At",
+    "Ended At",
+  ];
 
   const rows = sessions.map((session) => {
-    const totals = getSessionTotals(session)
-    const title = session.title?.trim() || session.messages[0]?.content.slice(0, 200).trim() || ''
+    const totals = getSessionTotals(session);
+    const title =
+      session.title?.trim() ||
+      session.messages[0]?.content.slice(0, 200).trim() ||
+      "";
 
     return [
       session.id,
       session.user.name,
       session.project.name,
       title,
-      session.messages[0]?.content ?? '',
+      session.messages[0]?.content ?? "",
       totals.inputTokens,
       totals.outputTokens,
       totals.estimatedCostUsd,
       session._count.events,
       session.startedAt.toISOString(),
-      session.endedAt?.toISOString() ?? '',
-    ].map(csvField).join(',')
-  })
+      session.endedAt?.toISOString() ?? "",
+    ]
+      .map(csvField)
+      .join(",");
+  });
 
-  return `\uFEFF${[headers.join(','), ...rows].join('\r\n')}`
+  return `\uFEFF${[headers.join(","), ...rows].join("\r\n")}`;
 }
 
 // GET /api/orgs/:orgSlug/dashboard/sessions?from=&to=&projectId=&page=&pageSize=&sort=recent|cost
 export async function GET(
   req: NextRequest,
-  { params }: { params: Promise<{ orgSlug: string }> }
+  { params }: { params: Promise<{ orgSlug: string }> },
 ) {
   try {
-    const auth = await requireAuth(req)
-    if (auth instanceof NextResponse) return auth
-    const { userId } = auth
-    const { orgSlug } = await params
+    const auth = await requireAuth(req);
+    if (auth instanceof NextResponse) return auth;
+    const { userId } = auth;
+    const { orgSlug } = await params;
 
-    const access = await assertOrgAccessBySlugOrResponse(orgSlug, userId)
-    if (access instanceof NextResponse) return access
+    const access = await assertOrgAccessBySlugOrResponse(orgSlug, userId);
+    if (access instanceof NextResponse) return access;
 
     // Viewer 차단: 세션 목록은 title에 HUMAN 프롬프트 원문(PII 가능)이 포함되므로 전체 금지.
     if (!canAccessIndividualData(access.role)) {
-      return forbiddenByRole(access.role, 'MEMBER 이상')
+      return forbiddenByRole(access.role, "MEMBER 이상");
     }
 
-    const projectIdParam = req.nextUrl.searchParams.get('projectId')
-    const projectIds = await resolveOrgScopedProjectIds(access.org.id, userId, access.role, projectIdParam)
-    if (projectIds instanceof NextResponse) return projectIds
+    const projectIdParam = req.nextUrl.searchParams.get("projectId");
+    const projectIds = await resolveOrgScopedProjectIds(
+      access.org.id,
+      userId,
+      access.role,
+      projectIdParam,
+    );
+    if (projectIds instanceof NextResponse) return projectIds;
 
-    const fromQuery = req.nextUrl.searchParams.get('from') ?? undefined
-    const toQuery = req.nextUrl.searchParams.get('to') ?? undefined
-    const { from, to } = parseDateRange(fromQuery, toQuery)
+    const fromQuery = req.nextUrl.searchParams.get("from") ?? undefined;
+    const toQuery = req.nextUrl.searchParams.get("to") ?? undefined;
+    const { from, to } = parseDateRange(fromQuery, toQuery);
 
     const { page, pageSize, skip, take } = parsePagination(
-      req.nextUrl.searchParams.get('page'),
-      req.nextUrl.searchParams.get('pageSize'),
-    )
+      req.nextUrl.searchParams.get("page"),
+      req.nextUrl.searchParams.get("pageSize"),
+    );
 
-    const sortBy: 'cost' | 'recent' =
-      req.nextUrl.searchParams.get('sort') === 'cost' ? 'cost' : 'recent'
-    const wantsCsv = req.nextUrl.searchParams.get('format') === 'csv'
+    const sortBy: "cost" | "recent" =
+      req.nextUrl.searchParams.get("sort") === "cost" ? "cost" : "recent";
+    const wantsCsv = req.nextUrl.searchParams.get("format") === "csv";
 
-    const filenameFrom = from.toISOString().slice(0, 10)
-    const filenameTo = to.toISOString().slice(0, 10)
+    const filenameFrom = from.toISOString().slice(0, 10);
+    const filenameTo = to.toISOString().slice(0, 10);
     const csvHeaders = {
-      'Content-Type': 'text/csv; charset=utf-8',
-      'Content-Disposition': `attachment; filename="sessions-${orgSlug}-${filenameFrom}-to-${filenameTo}.csv"`,
-    }
+      "Content-Type": "text/csv; charset=utf-8",
+      "Content-Disposition": `attachment; filename="sessions-${orgSlug}-${filenameFrom}-to-${filenameTo}.csv"`,
+    };
 
     // projectIds 가 비었으면 (org 에 project 가 하나도 없음) 즉시 빈 결과 반환
     if (projectIds.length === 0) {
       if (wantsCsv) {
-        return new NextResponse(buildSessionsCsv([]), { headers: csvHeaders })
+        return new NextResponse(buildSessionsCsv([]), { headers: csvHeaders });
       }
-      const body: PaginatedResult<SessionItem> = { items: [], total: 0, page, pageSize }
-      return NextResponse.json(body)
+      const body: PaginatedResult<SessionItem> = {
+        items: [],
+        total: 0,
+        page,
+        pageSize,
+      };
+      return NextResponse.json(body);
     }
 
     const where = {
       projectId: { in: projectIds },
       startedAt: { gte: from, lte: to },
-    }
+    };
 
     if (wantsCsv) {
-      let csvSessions: SessionWithInclude[]
+      let csvSessions: SessionWithInclude[];
 
-      if (sortBy === 'cost') {
+      if (sortBy === "cost") {
         const rankedRows = await db.$queryRaw<Array<{ id: string }>>`
           SELECT cs.id
           FROM claude_sessions cs
@@ -186,35 +212,37 @@ export async function GET(
           ORDER BY COALESCE(SUM(ur.estimated_cost_usd), 0) DESC,
                    cs.started_at DESC,
                    cs.id ASC
-        `
-        const ids = rankedRows.map((r) => r.id)
+        `;
+        const ids = rankedRows.map((r) => r.id);
         if (ids.length === 0) {
-          csvSessions = []
+          csvSessions = [];
         } else {
           const rows = await db.claudeSession.findMany({
             where: { id: { in: ids } },
             include: sessionInclude,
-          })
-          const byId = new Map(rows.map((s) => [s.id, s]))
+          });
+          const byId = new Map(rows.map((s) => [s.id, s]));
           csvSessions = ids
             .map((id) => byId.get(id))
-            .filter((s): s is SessionWithInclude => !!s)
+            .filter((s): s is SessionWithInclude => !!s);
         }
       } else {
         csvSessions = await db.claudeSession.findMany({
           where,
           include: sessionInclude,
-          orderBy: { startedAt: 'desc' },
-        })
+          orderBy: { startedAt: "desc" },
+        });
       }
 
-      return new NextResponse(buildSessionsCsv(csvSessions), { headers: csvHeaders })
+      return new NextResponse(buildSessionsCsv(csvSessions), {
+        headers: csvHeaders,
+      });
     }
 
-    let sessions: SessionWithInclude[]
-    let total: number
+    let sessions: SessionWithInclude[];
+    let total: number;
 
-    if (sortBy === 'cost') {
+    if (sortBy === "cost") {
       // 1) SUM(estimated_cost_usd) 기준으로 해당 페이지의 session id만 먼저 뽑는다.
       //    tie-breaker: started_at desc → id asc 로 페이지 경계를 안정화.
       const [rankedRows, countResult] = await Promise.all([
@@ -232,43 +260,43 @@ export async function GET(
           LIMIT ${take} OFFSET ${skip}
         `,
         db.claudeSession.count({ where }),
-      ])
-      total = countResult
+      ]);
+      total = countResult;
 
-      const ids = rankedRows.map((r) => r.id)
+      const ids = rankedRows.map((r) => r.id);
       if (ids.length === 0) {
-        sessions = []
+        sessions = [];
       } else {
         // 2) 해당 id들만 기존 include 구조로 하이드레이션 후 rank 순서 복원.
         const rows = await db.claudeSession.findMany({
           where: { id: { in: ids } },
           include: sessionInclude,
-        })
-        const byId = new Map(rows.map((s) => [s.id, s]))
+        });
+        const byId = new Map(rows.map((s) => [s.id, s]));
         sessions = ids
           .map((id) => byId.get(id))
-          .filter((s): s is SessionWithInclude => !!s)
+          .filter((s): s is SessionWithInclude => !!s);
       }
     } else {
       const [rows, countResult] = await Promise.all([
         db.claudeSession.findMany({
           where,
           include: sessionInclude,
-          orderBy: { startedAt: 'desc' },
+          orderBy: { startedAt: "desc" },
           skip,
           take,
         }),
         db.claudeSession.count({ where }),
-      ])
-      sessions = rows
-      total = countResult
+      ]);
+      sessions = rows;
+      total = countResult;
     }
 
-    const items: SessionItem[] = sessions.map(mapSessionItem)
+    const items: SessionItem[] = sessions.map(mapSessionItem);
 
-    const body: PaginatedResult<SessionItem> = { items, total, page, pageSize }
-    return NextResponse.json(body)
+    const body: PaginatedResult<SessionItem> = { items, total, page, pageSize };
+    return NextResponse.json(body);
   } catch (err) {
-    return handleRouteError(err)
+    return handleRouteError(err);
   }
 }