CVE-2021-26690 — AI Deep Analysis Summary

🚨 **Essence**: A NULL pointer dereference in `mod_session`. <br>💥 **Consequences**: Remote attackers send crafted data to crash Apache child processes. Result: **Denial of Service (DoS)**.…

🛠️ **Root Cause**: Code flaw in Apache's `mod_session` module. <br>🔍 **Flaw**: Improper handling of a NULL pointer. When specific session data is processed, the code tries to dereference a NULL pointer, causing a crash.…

📦 **Affected**: Apache HTTP Server. <br>📅 **Versions**: Specifically **2.4.0 to 2.4.46**. <br>⚠️ **Note**: EasyApache 4 versions from 2017 are also listed as impacted. Check your specific build version! 🔎

🎯 **Attacker Action**: Execute a **DoS attack**. <br>🚫 **Impact**: Crashes worker processes. <br>🔒 **Limitation**: No direct code execution or data theft mentioned.…

📊 **Threshold**: **Low**. <br>🌐 **Auth**: Remote exploitation. No authentication required. <br>⚙️ **Config**: Requires `mod_session` to be enabled.…

💻 **Public Exp?**: **Yes**. <br>🔗 **PoCs**: Multiple GitHub repositories exist (e.g., `CVE-2021-26690` by `7own`, `0xdeviner`).…

🔍 **Self-Check**: <br>1. Check Apache version (`httpd -v`). <br>2. Verify if `mod_session` is loaded. <br>3. Use scanners to detect NULL pointer dereference patterns in session handling. <br>4.…

🛡️ **Official Fix**: **Yes**. <br>📝 **Patch**: Apache released security updates. <br>🔗 **Ref**: See Apache security advisories and vendor alerts (Oracle, Gentoo, Debian). Update to the latest stable version immediately!…

🚧 **No Patch? Workarounds**: <br>1. **Disable `mod_session`** if not needed. <br>2. Implement **WAF rules** to block malformed session headers. <br>3. Restart services frequently to mitigate DoS impact (temporary).…

🔥 **Urgency**: **High**. <br>⚡ **Priority**: Patch immediately. <br>📉 **Risk**: Easy remote DoS. No auth needed. Public exploits exist.…