CVE-2020-26259 — AI Deep Analysis Summary

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

🚨 **Essence**: XStream < 1.4.15 suffers from **Arbitrary File Deletion** via unmarshalling. 💥 **Consequences**: Attackers can delete **any known file** on the host system. Critical integrity loss! 📉

Q: Root Cause? (CWE/Flaw)

🛡️ **Root Cause**: **CWE-78** (OS Command Injection). 🔍 **Flaw**: Unsafe handling of unmarshalled XML data allows execution of system commands to remove files. ⚠️

Q: Who is affected? (Versions/Components)

📦 **Affected**: **XStream** library. 📅 **Versions**: **1.4.14 and earlier**. 🏢 **Vendor**: x-stream. Check your `pom.xml` dependencies! 🧐

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

🔓 **Exploitation**: **Remote** (AV:N). 🔐 **Auth**: **None Required** (PR:N). 👀 **UI**: **None Required** (UI:N). 🎯 **Complexity**: **High** (AC:H). Needs specific XML payload crafting. 🧩

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

💣 **Public Exp?**: **YES**. 🔗 **PoCs Available**: Multiple GitHub repos (e.g., jas502n, Al1ex). 🌐 **Wild Exploitation**: Possible if AC:H is bypassed or targeted. 🚀

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

🩹 **Fixed?**: **YES**. 📦 **Patch**: Upgrade to **XStream 1.4.15+**. 📢 **Vendor Advisory**: Official fix released. Struts also upgraded to fix this. ✅

Q: What if no patch? (Workaround)

🚧 **No Patch?**: Implement **Strict Input Validation**. 🛡️ **Mitigation**: Use `XStream.setupDefaultSecurity()` or custom `Converter` filters. 🚫 **Block**: Restrict XML unmarshalling sources. 🧱

Q: Is it urgent? (Priority Suggestion)

⚡ **Urgency**: **HIGH**. 🔥 **Priority**: Patch immediately! 📉 **Risk**: Remote, No Auth, High Integrity Impact. Even with High AC, the impact is severe. 🚨

Updated May 08, 2026 CVSS 6.8 · 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**: XStream < 1.4.15 suffers from **Arbitrary File Deletion** via unmarshalling. <br>💥 **Consequences**: Attackers can delete **any known file** on the host system. Critical integrity loss! 📉

Q2Root Cause? (CWE/Flaw)

🛡️ **Root Cause**: **CWE-78** (OS Command Injection). <br>🔍 **Flaw**: Unsafe handling of unmarshalled XML data allows execution of system commands to remove files. ⚠️

Q3Who is affected? (Versions/Components)

📦 **Affected**: **XStream** library. <br>📅 **Versions**: **1.4.14 and earlier**. <br>🏢 **Vendor**: x-stream. Check your `pom.xml` dependencies! 🧐

Q4What can hackers do? (Privileges/Data)

🕵️ **Attacker Action**: Delete **arbitrary files** on the local host. <br>🔑 **Privileges**: Requires sufficient process rights.…

Read full answer (login)

Q5Is exploitation threshold high? (Auth/Config)

🔓 **Exploitation**: **Remote** (AV:N). <br>🔐 **Auth**: **None Required** (PR:N). <br>👀 **UI**: **None Required** (UI:N). <br>🎯 **Complexity**: **High** (AC:H). Needs specific XML payload crafting. 🧩

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

💣 **Public Exp?**: **YES**. <br>🔗 **PoCs Available**: Multiple GitHub repos (e.g., jas502n, Al1ex). <br>🌐 **Wild Exploitation**: Possible if AC:H is bypassed or targeted. 🚀

Q7How to self-check? (Features/Scanning)

🔍 **Self-Check**: Scan for **XStream** dependency version. <br>📝 **Code Review**: Look for `XStream.unmarshal()` usage without security filters.…

Read full answer (login)

Q8Is it fixed officially? (Patch/Mitigation)

🩹 **Fixed?**: **YES**. <br>📦 **Patch**: Upgrade to **XStream 1.4.15+**. <br>📢 **Vendor Advisory**: Official fix released. Struts also upgraded to fix this. ✅

Q9What if no patch? (Workaround)

🚧 **No Patch?**: Implement **Strict Input Validation**. <br>🛡️ **Mitigation**: Use `XStream.setupDefaultSecurity()` or custom `Converter` filters. <br>🚫 **Block**: Restrict XML unmarshalling sources. 🧱

Q10Is it urgent? (Priority Suggestion)

⚡ **Urgency**: **HIGH**. <br>🔥 **Priority**: Patch immediately! <br>📉 **Risk**: Remote, No Auth, High Integrity Impact. Even with High AC, the impact is severe. 🚨

Continue exploring

Vulnerability detail Full AI analysis (login) x-stream CWE-78