CVE-2021-34429 — AI Deep Analysis Summary

Q: What is this vulnerability? (Essence + Consequences)

🚨 **Essence**: Eclipse Jetty allows attackers to bypass security constraints using encoded URIs. 📉 **Consequences**: Sensitive files in the `WEB-INF` directory can be disclosed, leading to information leakage.

Q: Root Cause? (CWE/Flaw)

🛡️ **Root Cause**: CWE-200 (Information Exposure). The flaw lies in improper authorization handling where encoded characters trick the server into revealing protected content.

Q: Who is affected? (Versions/Components)

📦 **Affected Versions**: - Jetty 9.4.37 - 9.4.42 - Jetty 10.0.1 - 10.0.5 - Jetty 11.0.1 - 11.0.5 🏢 **Vendor**: The Eclipse Foundation.

Q: What can hackers do? (Privileges/Data)

💀 **Attacker Capabilities**: - Access `WEB-INF` contents (usually restricted). - Bypass security constraints. - Obtain sensitive configuration/data. - Potential for unauthorized admin operations.

Q: Is exploitation threshold high? (Auth/Config)

⚡ **Exploitation Threshold**: LOW. - **Auth**: None required (PR:N). - **Network**: Remote (AV:N). - **Complexity**: Low (AC:L). No user interaction needed (UI:N).

Q: Is there a public Exp? (PoC/Wild Exploitation)

🔓 **Public Exploits**: YES. Multiple PoCs exist on GitHub (e.g., ColdFusionX, Nuclei templates). Wild exploitation is highly feasible due to simple URI encoding tricks.

Q: How to self-check? (Features/Scanning)

🔍 **Self-Check**: - Scan for Jetty versions listed above. - Use Nuclei templates for CVE-2021-34429. - Test if encoded URIs access `/WEB-INF/` paths. - Check for similar patterns to CVE-2021-28164.

Q: What if no patch? (Workaround)

🛠️ **No Patch Workaround**: - Implement WAF rules to block encoded URI patterns targeting `WEB-INF`. - Restrict direct access to `WEB-INF` at the reverse proxy level (Nginx/Apache). - Disable unnecessary Jetty features.

Q: Is it urgent? (Priority Suggestion)

🔥 **Urgency**: HIGH. CVSS Score indicates easy remote exploitation with data leakage impact. Immediate patching or WAF mitigation is recommended for all affected instances.

Updated May 06, 2026 CVSS 5.3 · Medium

This is a summary of the AI-generated 10-question deep analysis. The full version (longer answers, follow-up Q&A, related CVEs) requires login. Read the full analysis →

Q1What is this vulnerability? (Essence + Consequences)

🚨 **Essence**: Eclipse Jetty allows attackers to bypass security constraints using encoded URIs. 📉 **Consequences**: Sensitive files in the `WEB-INF` directory can be disclosed, leading to information leakage.

Q2Root Cause? (CWE/Flaw)

🛡️ **Root Cause**: CWE-200 (Information Exposure). The flaw lies in improper authorization handling where encoded characters trick the server into revealing protected content.

Q3Who is affected? (Versions/Components)

📦 **Affected Versions**: 
- Jetty 9.4.37 - 9.4.42
- Jetty 10.0.1 - 10.0.5
- Jetty 11.0.1 - 11.0.5
🏢 **Vendor**: The Eclipse Foundation.

Q4What can hackers do? (Privileges/Data)

💀 **Attacker Capabilities**: 
- Access `WEB-INF` contents (usually restricted).
- Bypass security constraints.
- Obtain sensitive configuration/data.
- Potential for unauthorized admin operations.

Q5Is exploitation threshold high? (Auth/Config)

⚡ **Exploitation Threshold**: LOW. 
- **Auth**: None required (PR:N).
- **Network**: Remote (AV:N).
- **Complexity**: Low (AC:L). No user interaction needed (UI:N).

Q6Is there a public Exp? (PoC/Wild Exploitation)

🔓 **Public Exploits**: YES. Multiple PoCs exist on GitHub (e.g., ColdFusionX, Nuclei templates). Wild exploitation is highly feasible due to simple URI encoding tricks.

Q7How to self-check? (Features/Scanning)

🔍 **Self-Check**: 
- Scan for Jetty versions listed above.
- Use Nuclei templates for CVE-2021-34429.
- Test if encoded URIs access `/WEB-INF/` paths.
- Check for similar patterns to CVE-2021-28164.

Q8Is it fixed officially? (Patch/Mitigation)

✅ **Official Fix**: YES. The vendor released patches.…

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Q9What if no patch? (Workaround)

🛠️ **No Patch Workaround**: 
- Implement WAF rules to block encoded URI patterns targeting `WEB-INF`.
- Restrict direct access to `WEB-INF` at the reverse proxy level (Nginx/Apache).
- Disable unnecessary Jetty features.

Q10Is it urgent? (Priority Suggestion)

🔥 **Urgency**: HIGH. CVSS Score indicates easy remote exploitation with data leakage impact. Immediate patching or WAF mitigation is recommended for all affected instances.

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Vulnerability detail Full AI analysis (login) The Eclipse Foundation CWE-200