CVE-2023-6816 — AI Deep Analysis Summary

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

🚨 **Essence**: Heap Overflow in X.org Server. 💥 **Consequences**: Crash, Data Corruption, or Remote Code Execution. The server allocates memory for a fixed number of buttons, but larger values cause a heap overflow.

Q: Root Cause? (CWE/Flaw)

🛡️ **CWE**: CWE-787 (Out-of-bounds Write). 🔍 **Flaw**: Improper allocation of memory space for device-specific buttons. Using a value larger than allocated causes the overflow.

Q: Who is affected? (Versions/Components)

📦 **Affected**: X.org Server versions **before 21.1.11**. 🏢 **Vendor Context**: Red Hat Enterprise Linux 6 (Extended Lifecycle Support).

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

💀 **Impact**: High (CVSS 9.8). 🔓 **Privileges**: Complete system compromise. 📊 **Data**: Full Confidentiality, Integrity, and Availability loss. Attackers can execute arbitrary code.

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

⚡ **Threshold**: LOW. 🔑 **Auth**: None required (PR:N). 🌐 **Vector**: Network (AV:N). 👁️ **UI**: None required (UI:N). Easy to exploit remotely.

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

📜 **Public Exp**: No specific PoC listed in data. 📢 **Advisories**: Red Hat (RHSA-2025:12751, RHSA-2024:2995), Gentoo, Fedora announcements exist. Wild exploitation risk is high due to low complexity.

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

🔍 **Check**: Scan for X.org Server version < 21.1.11. 📋 **Verify**: Check Red Hat errata RHSA-2024:2995 or RHSA-2025:12751 for patch status.

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

✅ **Fixed**: YES. 🛠️ **Action**: Update X.org Server to version **21.1.11 or later**. 📥 **Source**: Red Hat Security Advisories (RHSA) provide the official patches.

Q: What if no patch? (Workaround)

🚧 **Workaround**: If patching is delayed, restrict network access to X.org services. 🛑 **Mitigation**: Disable unnecessary X11 forwarding or remote display services to reduce attack surface.

Q: Is it urgent? (Priority Suggestion)

🔥 **Urgency**: CRITICAL. ⏱️ **Priority**: Immediate. 📉 **Risk**: CVSS 9.8 (Critical) + Network Access + No Auth. Patch immediately to prevent RCE.

Updated May 08, 2026 CVSS 9.8 · Critical

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**: Heap Overflow in X.org Server. <br>💥 **Consequences**: Crash, Data Corruption, or Remote Code Execution. The server allocates memory for a fixed number of buttons, but larger values cause a heap overflow.

Q2Root Cause? (CWE/Flaw)

🛡️ **CWE**: CWE-787 (Out-of-bounds Write). <br>🔍 **Flaw**: Improper allocation of memory space for device-specific buttons. Using a value larger than allocated causes the overflow.

Q3Who is affected? (Versions/Components)

📦 **Affected**: X.org Server versions **before 21.1.11**. <br>🏢 **Vendor Context**: Red Hat Enterprise Linux 6 (Extended Lifecycle Support).

Q4What can hackers do? (Privileges/Data)

💀 **Impact**: High (CVSS 9.8). <br>🔓 **Privileges**: Complete system compromise. <br>📊 **Data**: Full Confidentiality, Integrity, and Availability loss. Attackers can execute arbitrary code.

Q5Is exploitation threshold high? (Auth/Config)

⚡ **Threshold**: LOW. <br>🔑 **Auth**: None required (PR:N). <br>🌐 **Vector**: Network (AV:N). <br>👁️ **UI**: None required (UI:N). Easy to exploit remotely.

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

📜 **Public Exp**: No specific PoC listed in data. <br>📢 **Advisories**: Red Hat (RHSA-2025:12751, RHSA-2024:2995), Gentoo, Fedora announcements exist. Wild exploitation risk is high due to low complexity.

Q7How to self-check? (Features/Scanning)

🔍 **Check**: Scan for X.org Server version < 21.1.11. <br>📋 **Verify**: Check Red Hat errata RHSA-2024:2995 or RHSA-2025:12751 for patch status.

Q8Is it fixed officially? (Patch/Mitigation)

✅ **Fixed**: YES. <br>🛠️ **Action**: Update X.org Server to version **21.1.11 or later**. <br>📥 **Source**: Red Hat Security Advisories (RHSA) provide the official patches.

Q9What if no patch? (Workaround)

🚧 **Workaround**: If patching is delayed, restrict network access to X.org services. <br>🛑 **Mitigation**: Disable unnecessary X11 forwarding or remote display services to reduce attack surface.

Q10Is it urgent? (Priority Suggestion)

🔥 **Urgency**: CRITICAL. <br>⏱️ **Priority**: Immediate. <br>📉 **Risk**: CVSS 9.8 (Critical) + Network Access + No Auth. Patch immediately to prevent RCE.

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Vulnerability detail Full AI analysis (login) Red Hat CWE-787