CVE-2021-26085 — AI Deep Analysis Summary

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

🚨 **Essence**: Pre-authorization arbitrary file read via `/s/` endpoint. 💥 **Consequences**: Attackers can view restricted resources (like config files) without logging in. Critical info leak! 📄

Q: Root Cause? (CWE/Flaw)

🛡️ **Root Cause**: Path traversal/Local File Inclusion (LFI) flaw in the `/s/` endpoint handling. 🔍 **CWE**: Not specified in data, but effectively an **Access Control Bypass** allowing unauthorized file access.

Q: Who is affected? (Versions/Components)

📦 **Affected**: Atlassian Confluence Server. 📉 **Versions**: • < 7.4.10 • 7.5.0 - 7.12.2 (specifically < 7.12.3). ✅ **Safe**: 7.4.10+ and 7.12.3+.

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

🕵️ **Hackers Can**: Read sensitive internal files. 📂 **Targets**: `WEB-INF/web.xml`, `seraph-config.xml`, `pom.xml`. 🔑 **Data**: Configuration details, potentially credentials or internal architecture info.

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

⚡ **Threshold**: **LOW**. 🔓 **Auth**: **Pre-authorization** required! No login needed. 🌐 **Access**: Remote execution via simple HTTP GET requests.

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

🔓 **Public Exp?**: **YES**. 📜 **PoC**: Available on GitHub (ColdFusionX) and Nuclei templates. 🌍 **Wild Exp**: High risk due to ease of use and lack of auth requirement.

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

🔍 **Self-Check**: 1. Check Confluence version. 2. Scan for `/s/123cfx/_/;/WEB-INF/web.xml` response. 3. Use Nuclei template `CVE-2021-26085.yaml` for automated detection.

Q: Is it fixed officially? (Patch/Mitigation)

🛠️ **Official Fix**: **YES**. 📥 **Action**: Upgrade to **7.4.10** or **7.12.3** (or later). 🔗 **Ref**: Atlassian Jira CONFSERVER-67893.

Q: What if no patch? (Workaround)

🚧 **No Patch?**: 1. **Block** `/s/` endpoint via WAF/NGINX. 2. **Restrict** access to `/WEB-INF/` paths. 3. **Isolate** server from public internet if possible.

Q: Is it urgent? (Priority Suggestion)

🔥 **Urgency**: **CRITICAL**. ⏱️ **Priority**: **P1**. 💡 **Reason**: No auth needed + Public PoC + Sensitive data exposure. Patch immediately! 🏃♂️💨

Updated May 06, 2026

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**: Pre-authorization arbitrary file read via `/s/` endpoint. <br>💥 **Consequences**: Attackers can view restricted resources (like config files) without logging in. Critical info leak! 📄

Q2Root Cause? (CWE/Flaw)

🛡️ **Root Cause**: Path traversal/Local File Inclusion (LFI) flaw in the `/s/` endpoint handling. <br>🔍 **CWE**: Not specified in data, but effectively an **Access Control Bypass** allowing unauthorized file access.

Q3Who is affected? (Versions/Components)

📦 **Affected**: Atlassian Confluence Server. <br>📉 **Versions**: <br>• < 7.4.10 <br>• 7.5.0 - 7.12.2 (specifically < 7.12.3). <br>✅ **Safe**: 7.4.10+ and 7.12.3+.

Q4What can hackers do? (Privileges/Data)

🕵️ **Hackers Can**: Read sensitive internal files. <br>📂 **Targets**: `WEB-INF/web.xml`, `seraph-config.xml`, `pom.xml`. <br>🔑 **Data**: Configuration details, potentially credentials or internal architecture info.

Q5Is exploitation threshold high? (Auth/Config)

⚡ **Threshold**: **LOW**. <br>🔓 **Auth**: **Pre-authorization** required! No login needed. <br>🌐 **Access**: Remote execution via simple HTTP GET requests.

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

🔓 **Public Exp?**: **YES**. <br>📜 **PoC**: Available on GitHub (ColdFusionX) and Nuclei templates. <br>🌍 **Wild Exp**: High risk due to ease of use and lack of auth requirement.

Q7How to self-check? (Features/Scanning)

🔍 **Self-Check**: <br>1. Check Confluence version. <br>2. Scan for `/s/123cfx/_/;/WEB-INF/web.xml` response. <br>3. Use Nuclei template `CVE-2021-26085.yaml` for automated detection.

Q8Is it fixed officially? (Patch/Mitigation)

🛠️ **Official Fix**: **YES**. <br>📥 **Action**: Upgrade to **7.4.10** or **7.12.3** (or later). <br>🔗 **Ref**: Atlassian Jira CONFSERVER-67893.

Q9What if no patch? (Workaround)

🚧 **No Patch?**: <br>1. **Block** `/s/` endpoint via WAF/NGINX. <br>2. **Restrict** access to `/WEB-INF/` paths. <br>3. **Isolate** server from public internet if possible.

Q10Is it urgent? (Priority Suggestion)

🔥 **Urgency**: **CRITICAL**. <br>⏱️ **Priority**: **P1**. <br>💡 **Reason**: No auth needed + Public PoC + Sensitive data exposure. Patch immediately! 🏃‍♂️💨

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