Update CHANGELOG.md with critical fixes for memory corruption and large file transfer issues

- Documented wssshd memory corruption fix with bounds checking and validation
- Added details about WebSocket frame size reduction for large file transfers
- Explained technical fixes for heap corruption and network reliability issues

CHANGELOG.md

@@ -22,7 +22,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   - `--enc bin`: Direct binary data transmission
   - Configuration file support with `enc = hex` option in `wsssht.conf`
   - Automatic encoding negotiation between wsssht and wssshc clients
-  - wsssh and wsscp can pass `--enc` option to ProxyCommand for wsssht
+
+- **Encoding Options for wsssh and wsscp**: Added optional `--enc` option to wsssh and wsscp
+  - Accepts `--enc hex|base64|bin` argument and passes it to wsssht ProxyCommand
+  - Allows users to specify encoding preference when using wrapper tools
+  - Maintains backward compatibility - option is completely optional
 
 ### Technical Details
 - **Encoding Architecture**: Extensible encoding system with per-tunnel encoding negotiation
@@ -34,6 +38,21 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - **Data Transmission Security**: Fixed corruption that could potentially cause data misinterpretation
 - **Protocol Compliance**: Proper encoding negotiation prevents data corruption attacks
 
+### Fixed
+- **Memory Corruption in wssshd**: Critical fix for heap corruption causing 'malloc(): invalid next size' errors
+  - Added bounds checking and validation for parameter extraction in tunnel request parsing
+  - Prevented buffer overflows by limiting parameter lengths to reasonable sizes (< 32 chars)
+  - Added null pointer and bounds validation before string operations
+  - Increased request message buffer size from 512 to 1024 bytes for safety
+  - Fixed potential heap metadata corruption from malformed JSON messages
+
+- **Large WebSocket Frame Issues**: Fixed SSL write failures during large file transfers
+  - Reduced MAX_CHUNK_SIZE from 65536 (64KB) to 4096 (4KB) bytes
+  - Prevents creation of very large WebSocket frames (131KB+) that cause network timeouts
+  - Smaller chunks improve network reliability and reduce connection drop issues
+  - Hex-encoded 4KB data creates 8KB frames, which are much more network-friendly
+  - Maintains transfer performance while improving stability for large files
+
 ## [1.6.5] - 2025-09-19
 
 ### Added