FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to version 3.23.0, xf_clipboard_format_equal reads freed lastSentFormats memory because xf_clipboard_formats_free (called from the cliprdr channel thread during auto-reconnect) frees the array while the X11 event thread concurrently iterates it in xf_clipboard_changed, triggering a heap use after free. Version 3.23.0 fixes the issue.
Weakness
The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory “belongs” to the code that operates on the new pointer.
Affected Software
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Freerdp | Freerdp | * | 3.23.0 (excluding) |
Potential Mitigations
References
- https://github.com/FreeRDP/FreeRDP/blob/5c7aae27d0417b42b4806c2a5c583ca39dd9ef1e/client/X11/xf_cliprdr.c#L1884
- https://github.com/FreeRDP/FreeRDP/blob/5c7aae27d0417b42b4806c2a5c583ca39dd9ef1e/client/X11/xf_cliprdr.c#L1889
- https://github.com/FreeRDP/FreeRDP/blob/5c7aae27d0417b42b4806c2a5c583ca39dd9ef1e/client/X11/xf_cliprdr.c#L265
- https://github.com/FreeRDP/FreeRDP/blob/5c7aae27d0417b42b4806c2a5c583ca39dd9ef1e/client/X11/xf_cliprdr.c#L616
- https://github.com/FreeRDP/FreeRDP/blob/5c7aae27d0417b42b4806c2a5c583ca39dd9ef1e/client/X11/xf_cliprdr.c#L831
- https://github.com/FreeRDP/FreeRDP/blob/5c7aae27d0417b42b4806c2a5c583ca39dd9ef1e/client/X11/xf_cliprdr.c#L851-L855
- https://github.com/FreeRDP/FreeRDP/blob/5c7aae27d0417b42b4806c2a5c583ca39dd9ef1e/client/X11/xf_cliprdr.c#L868-L875
- https://github.com/FreeRDP/FreeRDP/commit/58409406afe7c2a8a71ed2dc8e22075be4f41c0c
- https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-q5j3-m6jf-3jq4
- https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-q5j3-m6jf-3jq4