fix: Secure Resume Upload Processing Against Malicious PDF and DOCX Files

[Krishnx21]

Fixes #5489

Description

This PR addresses a critical security and reliability issue in the resume upload pipeline where untrusted PDF and DOCX files are parsed directly within the application process.

The current implementation reads uploaded files into memory and processes them using document parsing libraries (pdf-parse and mammoth) without isolation, resource constraints, or decompression safeguards. Since DOCX files are ZIP-based archives and PDFs can contain complex structures, specially crafted files can consume excessive CPU and memory resources, potentially causing denial-of-service conditions.

Affected Components
app/api/student/resume/upload/route.ts
lib/resume-parser.ts
Changes Made

1. Isolated Document Processing

Moved document parsing into a dedicated worker process instead of executing directly within the request handler.

Benefits:

Prevents parser failures from affecting API availability
Isolates resource-intensive operations
Improves application stability
2. Added Parsing Timeouts

Introduced execution time limits for document processing.

Features:

Automatic termination of long-running parsing tasks
Protection against parser hangs
Reduced risk of CPU exhaustion attacks
3. Added Memory Usage Controls

Implemented safeguards to prevent excessive memory allocation during parsing.

Protections include:

Maximum parser memory limits
Large-buffer rejection
Controlled extraction operations
4. Added DOCX Archive Validation

Introduced ZIP archive inspection before DOCX processing.

Validation includes:

Maximum file count checks
Maximum extracted size checks
Compression ratio validation
ZIP bomb detection
5. Added PDF Safety Checks

Implemented PDF validation before parsing.

Checks include:

Maximum page limits
Maximum object limits
File structure validation
Rejection of suspicious PDFs
6. Added Extracted Content Limits

Restricted the amount of text that can be extracted from uploaded documents.

Benefits:

Prevents oversized extraction payloads
Reduces memory pressure
Improves parser performance
7. Improved Error Handling

Added safer failure paths for malformed documents.

The system now:

Rejects invalid files gracefully
Returns meaningful validation errors
Avoids application crashes caused by parser exceptions
Security Impact

This PR mitigates:

PDF parser denial-of-service attacks
DOCX ZIP bomb attacks
CPU exhaustion attacks
Memory exhaustion attacks
Long-running parser abuse
Worker instability caused by malformed documents

Testing
Verified Scenarios
✅ Valid PDF resumes parse successfully
✅ Valid DOCX resumes parse successfully
✅ Malformed PDFs are rejected safely
✅ Malformed DOCX files are rejected safely
✅ Oversized extraction attempts are blocked
✅ Timeout protection terminates long-running parses
✅ ZIP bomb detection prevents excessive expansion
✅ Application remains responsive during parsing failures
Manual Testing
Upload a valid PDF resume.
Verify successful parsing.
Upload a valid DOCX resume.
Verify successful parsing.
Upload malformed documents.
Confirm safe rejection.
Upload highly compressed test archives.
Verify decompression limits trigger correctly.
Confirm API responsiveness remains unaffected.
Performance Benefits
Improved service stability
Better resource management
Reduced risk of worker crashes
Safer handling of user-supplied files

GSSoC 2026
Program: GSSoC 2026
Type: Security Fix

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[Krishnx21]

@Aamod007 @JhaSourav07 check it out ..

[Aamod007]

Strong security hardening. �pp/api/student/resume/upload/route.ts now sanitizes filenames, validates extension vs MIME type, and blocks encrypted or malformed inputs before parsing, while lib/resume-parser.ts adds worker isolation, timeout handling, and ZIP/PDF structure checks to keep untrusted documents from destabilizing the app.

[Aamod007]

Difficulty: critical – Secures Resume Upload Processing Against Malicious PDF and DOCX Files.

Quality: clean – Comprehensive security.

Type: security – File upload hardening.

Excellent security work!