FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to version 3.23.0, xf_cliprdr_provide_data_ passes freed pDstData to XChangeProperty because the cliprdr channel thread calls xf_cliprdr_server_format_data_response which converts and uses the clipboard data without holding any lock, while the X11 event thread concurrently calls xf_cliprdr_clear_cached_data → HashTable_Clear which frees the same data via xf_cached_data_free, 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 Any operations using the original pointer are no longer valid because the memory “belongs” to the code that operates on the new pointer.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#L1229-L1243
- https://github.com/FreeRDP/FreeRDP/blob/5c7aae27d0417b42b4806c2a5c583ca39dd9ef1e/client/X11/xf_cliprdr.c#L1337-L1344
- https://github.com/FreeRDP/FreeRDP/blob/5c7aae27d0417b42b4806c2a5c583ca39dd9ef1e/client/X11/xf_cliprdr.c#L200-L208
- https://github.com/FreeRDP/FreeRDP/blob/5c7aae27d0417b42b4806c2a5c583ca39dd9ef1e/client/X11/xf_cliprdr.c#L2295
- https://github.com/FreeRDP/FreeRDP/blob/5c7aae27d0417b42b4806c2a5c583ca39dd9ef1e/client/X11/xf_cliprdr.c#L2323-L2334
- https://github.com/FreeRDP/FreeRDP/blob/5c7aae27d0417b42b4806c2a5c583ca39dd9ef1e/client/X11/xf_cliprdr.c#L2363
- https://github.com/FreeRDP/FreeRDP/blob/5c7aae27d0417b42b4806c2a5c583ca39dd9ef1e/client/X11/xf_cliprdr.c#L933
- https://github.com/FreeRDP/FreeRDP/commit/d3e8b3b9365be96a4f11dda149d71b3287227d0a
- https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-78xg-v4p2-4w3c
- https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-78xg-v4p2-4w3c