FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to version 3.21.0, offscreen bitmap deletion leaves gdi->drawing pointing to freed memory, causing UAF when related update packets arrive. A malicious server can trigger a client‑side use after free, causing a crash (DoS) and potential heap corruption with code‑execution risk depending on allocator behavior and surrounding heap layout. Version 3.21.0 contains a patch for 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 Any operations using the original pointer are no longer valid because the memory “belongs” to the code that operates on the new pointer.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 | * | 3.21.0 (excluding) |
| Red Hat Enterprise Linux 10 | RedHat | freerdp-2:3.10.3-5.el10_1.1 | * |
| Red Hat Enterprise Linux 10.0 Extended Update Support | RedHat | freerdp-2:3.10.3-3.el10_0.1 | * |
| Red Hat Enterprise Linux 7 Extended Lifecycle Support | RedHat | freerdp-0:2.1.1-5.el7_9.1 | * |
| Red Hat Enterprise Linux 8 | RedHat | freerdp-2:2.11.7-2.el8_10 | * |
| Red Hat Enterprise Linux 9 | RedHat | freerdp-2:2.11.7-1.el9_7.1 | * |
| Red Hat Enterprise Linux 9.0 Update Services for SAP Solutions | RedHat | freerdp-2:2.4.1-3.el9_0 | * |
| Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions | RedHat | freerdp-2:2.4.1-6.el9_2.2 | * |
| Red Hat Enterprise Linux 9.4 Extended Update Support | RedHat | freerdp-2:2.11.2-1.el9_4.1 | * |
| Freerdp2 | Ubuntu | esm-apps/noble | * |
| Freerdp2 | Ubuntu | esm-infra/bionic | * |
| Freerdp2 | Ubuntu | esm-infra/focal | * |
| Freerdp2 | Ubuntu | jammy | * |
| Freerdp2 | Ubuntu | noble | * |
| Freerdp2 | Ubuntu | upstream | * |
| Freerdp3 | Ubuntu | noble | * |
| Freerdp3 | Ubuntu | questing | * |
| Freerdp3 | Ubuntu | upstream | * |
Potential Mitigations
References
- https://github.com/FreeRDP/FreeRDP/blob/3370e30e92a021eb680892dda14d642bc8b8727c/libfreerdp/cache/offscreen.c#L114-L122
- https://github.com/FreeRDP/FreeRDP/blob/3370e30e92a021eb680892dda14d642bc8b8727c/libfreerdp/cache/offscreen.c#L87-L91
- https://github.com/FreeRDP/FreeRDP/releases/tag/3.21.0
- https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-cfgj-vc84-f3pp