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Security audit

DeepSeek V4 Reasoning Bug

Security checks for vulnerabilities and agentic risk

Overview

This is a troubleshooting guide for a DeepSeek API compatibility bug, with no hidden install steps, persistence, or unrelated data access.

Install only if you are comfortable using a Chinese-language troubleshooting guide. If you run the reproduction snippet, use test prompts and test tool outputs rather than private user data or production credentials.

Vulnerability Patterns
  • Skill Instruction HijackingAlters the agent's session goals or safety constraints when the skill loads
  • Agent Memory PoisoningWrites attacker-controlled rules into memory that affect later sessions
  • Remote Payload Retrieval and ExecutionFetches external code whose behavior can change after review
  • Embedded Malicious CodeShips malicious scripts inside the skill and executes them locally
  • Unauthorized Access and Privilege EscalationObtains permissions beyond the task's legitimate needs
Vulnerability Patterns
  • Data ExfiltrationExternal Transmission, Env Variable Harvesting, File System Enumeration
  • Prompt InjectionInstruction Override, Hidden Instructions, Exfiltration Commands
  • Privilege EscalationExcessive Permissions, Sudo/Root Execution, Credential Access
  • Supply ChainUnpinned Dependencies, External Script Fetching, Obfuscated Code
  • Excessive AgencyUnrestricted Tool Access, Autonomous Decision Making, Scope Creep
Findings (7)

Natural-Language Policy Violations

Medium
Category
Not specified by scanner
Confidence
95% confidence
Finding

The manifest description and the instructional content are presented in Chinese, and the file does not indicate that the user can choose another language or that the skill is region- or locale-specific. This can violate language/locale policy because it effectively forces a specific language without user opt-in.

Content

No source excerpt is available for this finding.

External Transmission

Medium
Category
Data Exfiltration
Confidence
60% confidence
Finding

Data is being sent to an external URL. This could be legitimate telemetry or data exfiltration. Manual review is recommended.

Content

Scanner excerpt · SKILL.md (reported line 97)May include surrounding context.

md
import requests

# 1. 首次请求(带 thinking + tool calls)
response = requests.post("https://api.deepseek.com/v1/chat/completions", json={
    "model": "deepseek-v4-pro",
    "reasoning": {"effort": "low"},
    "messages": [

External Transmission

Medium
Category
Data Exfiltration
Confidence
60% confidence
Finding

Data is being sent to an external URL. This could be legitimate telemetry or data exfiltration. Manual review is recommended.

Content

Scanner excerpt · SKILL.md (reported line 111)May include surrounding context.

md
import requests

# 1. 首次请求(带 thinking + tool calls)
response = requests.post("https://api.deepseek.com/v1/chat/completions", json={
    "model": "deepseek-v4-pro",
    "reasoning": {"effort": "low"},
    "messages": [

External Transmission

Medium
Category
Data Exfiltration
Confidence
70% confidence
Finding

Data is being sent to an external URL. This could be legitimate telemetry or data exfiltration. Manual review is recommended.

Content

Scanner excerpt · SKILL.md (reported line 97)May include surrounding context.

md
import requests

# 1. 首次请求(带 thinking + tool calls)
response = requests.post("https://api.deepseek.com/v1/chat/completions", json={
    "model": "deepseek-v4-pro",
    "reasoning": {"effort": "low"},
    "messages": [

External Transmission

Medium
Category
Data Exfiltration
Confidence
70% confidence
Finding

Data is being sent to an external URL. This could be legitimate telemetry or data exfiltration. Manual review is recommended.

Content

Scanner excerpt · SKILL.md (reported line 111)May include surrounding context.

md
import requests

# 1. 首次请求(带 thinking + tool calls)
response = requests.post("https://api.deepseek.com/v1/chat/completions", json={
    "model": "deepseek-v4-pro",
    "reasoning": {"effort": "low"},
    "messages": [

External Transmission

Medium
Category
Data Exfiltration
Confidence
50% confidence
Finding

Data is being sent to an external URL. This could be legitimate telemetry or data exfiltration. Manual review is recommended.

Content

Scanner excerpt · SKILL.md (reported line 97)May include surrounding context.

md
import requests

# 1. 首次请求(带 thinking + tool calls)
response = requests.post("https://api.deepseek.com/v1/chat/completions", json={
    "model": "deepseek-v4-pro",
    "reasoning": {"effort": "low"},
    "messages": [

External Transmission

Medium
Category
Data Exfiltration
Confidence
50% confidence
Finding

Data is being sent to an external URL. This could be legitimate telemetry or data exfiltration. Manual review is recommended.

Content

Scanner excerpt · SKILL.md (reported line 111)May include surrounding context.

md
import requests

# 1. 首次请求(带 thinking + tool calls)
response = requests.post("https://api.deepseek.com/v1/chat/completions", json={
    "model": "deepseek-v4-pro",
    "reasoning": {"effort": "low"},
    "messages": [

Static analysis

No suspicious patterns detected.