Flare Zero day Research

Private File IDOR via raw/direct endpoints
GHSA : https://github.com/FlintSH/Flare/security/advisories/GHSA-gwqr-xf5c-5569 
 CVE : CVE-2026-30231 
 Summary 
 The raw and direct file routes only block unauthenticated users from accessing private files. Any authenticated, non‑owner user who knows the file URL can retrieve the content, which is inconsistent with stricter checks used by other endpoints 
 
 Evidence (Code References) 
 
 raw route predicate: raw/route.ts:L92-L97 
 direct route predicate: direct/route.ts:L35-L40 
 download route correct check: download/route.ts:L36-L45 
 thumbnail route correct check: thumbnail/route.ts:L32-L45 
 
 Impact 
 
 Confidential private files can be accessed by any authenticated user if the URL is known. 
 Violates access control consistency across file endpoints. 
 
 Expected vs Actual 
 
 Expected: Private files should be accessible only to the owner or admin. 
 Actual: Private files are accessible to any authenticated user on raw/direct routes. 
 
 Minimal Logic Reproduction (non‑network) 
 This demonstrates the misclassification using the same predicates. 
 type Session = { user?: { id: string; role?: 'ADMIN' | 'USER' } } | null

function rawIsPrivate(visibility: 'PUBLIC' | 'PRIVATE', session: Session) {
 return visibility === 'PRIVATE' && !session?.user
}

function directIsPrivate(visibility: 'PUBLIC' | 'PRIVATE', session: Session) {
 return visibility === 'PRIVATE' && !session?.user
}

// Setup: private file owned by A; authenticated B session
const fileVisibility = 'PRIVATE' as const
const sessionB: Session = { user: { id: 'user-B', role: 'USER' } }

// Current behavior in raw/direct:
rawIsPrivate(fileVisibility, sessionB) // false → grants access
directIsPrivate(fileVisibility, sessionB) // false → grants access

// Expected: deny unless owner or admin
function expectedIsPrivate(
 visibility: 'PUBLIC' | 'PRIVATE',
 session: Session,
 ownerId: string
) {
 const isOwner = session?.user?.id === ownerId
 const isAdmin = session?.user?.role === 'ADMIN'
 return visibility === 'PRIVATE' && !isOwner && !isAdmin
}
 
 Affected Components 
 
 raw file endpoint: raw/route.ts 
 direct file endpoint: direct/route.ts 
 
 Remediation 
 Align raw/direct with download/thumbnail: 
 const isOwner = session?.user?.id === file.userId
const isAdmin = session?.user?.role === 'ADMIN'
const isPrivate = file.visibility === 'PRIVATE' && !isOwner && !isAdmin

if (isPrivate) {
 return new Response(null, { status: 404 }) // or 403
}
 
 Consider centralizing access checks in a shared utility to ensure consistency across endpoints. 
 Verification Checklist 
 
 Private file as Owner A:
 
 Unauthenticated user → denied (404/401) 
 Authenticated non‑owner User B → denied 
 Admin → allowed 
 Owner → allowed 
 
 
 Behavior matches download/thumbnail routes. 
 Automated tests added for owner/admin/non‑owner/unauthenticated across raw/direct.

Password‑Protected Thumbnail Bypass
GHSA : https://github.com/FlintSH/Flare/security/advisories/GHSA-3x7v-x3r6-mjh7 
 CVE : CVE-2026-30230 
 Summary 
 The thumbnail endpoint does not validate the password for password‑protected files. It checks ownership/admin for private files but skips password verification, allowing thumbnail access without the password. 
 Affected Component 
 
 Thumbnail endpoint: thumbnail/route.ts 
 
 Evidence (Code References) 
 
 File password is fetched but never checked: thumbnail/route.ts:L32-L49 
 Password checks exist in other endpoints: 
 Download: download/route.ts:L50-L67 
 Raw: raw/route.ts:L99-L107 
 
 Video POC 
 
 Your browser does not support the video tag.
 
 Impact 
 
 Visual content of password‑protected files can be previewed through thumbnails without the password. 
 Information disclosure of sensitive images despite password protection. 
 
 Expected vs Actual 
 
 Expected: Password‑protected files require a valid password for any content access, including thumbnails. 
 Actual: Thumbnail content is served without password verification. 
 
 Reproduction Checklist 
 
 Create User A and upload an image with a password. 
 Note the file ID. 
 Log in as User B (non‑owner, non‑admin). 
 Request the thumbnail for User A’s file without providing the password. 
 Expected: access denied. 
 Actual: thumbnail returned. 
 
 Consider aligning thumbnail checks with the download/raw endpoints for consistent behavior. 
 Verification Checklist 
 
 Create a password‑protected image file. 
 Access thumbnail as:
 
 Unauthenticated user → denied 
 Authenticated non‑owner → denied unless password provided 
 Owner/admin → allowed 
 
 
 Confirm behavior matches download/raw endpoints.