CVE-2026-44421
FreeRDP RDPGFX CacheToSurface heap-buffer-overflow via clamped-rectangle validation bypass
- State
- Published
- Severity
- 8.8 High
- Published
- May 29, 2026
- Updated
- Jul 27, 2026
- Reserved
- May 6, 2026
Description
FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.26.0, a malicious RDP server can trigger a heap-buffer-overflow write in the FreeRDP client by sending crafted RDPGFX PDUs. The bug is in gdi_CacheToSurface: it validates a destination rectangle that is clamped to UINT16_MAX, but then performs the copy using the original cacheEntry->width/height. This can cause a large out-of-bounds heap write and may lead to client crashes or code execution. This bug is reachable from a malicious RDP server, but only when the client has RDPGFX enabled. This vulnerability is fixed in 3.26.0.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 3.1 | 8.8 High | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H | GitHub_M |
| 3.1 | 8.8 High | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H | redhat-SADP |
Weaknesses
Affected Products
| Product | Versions |
|---|---|
FreeRDPFreeRDP |
|
References
- https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-p6r2-4hgm-m6ff
- https://access.redhat.com/security/cve/CVE-2026-44421vdb-entry
- RHBZ#2483471issue-tracking
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-44421.json
- https://access.redhat.com/errata/RHSA-2026:46393vendor-advisory
- https://access.redhat.com/errata/RHSA-2026:36203vendor-advisory
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