CVE-2026-55827 FreeRDP: Heap out-of-bounds write in RemoteFX (RFX) Cache Bitmap V3 decode
A malicious RDP server can trigger a heap out-of-bounds write in FreeRDP clients using the non-default RemoteFX cache option, potentially leading to code execution.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-55827?
CVE-2026-55827 is a high-severity memory corruption vulnerability in Freerdp Freerdp, published on 10 Jul 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.27.1, FreeRDP clients launched with the non-default /cache:codec:rfx option pass desktop stride and height to RemoteFX decoding for Cache Bitmap V3 data while allocating bitmap->data only for the smaller DstWidth and DstHeight in gdi_Bitmap_Decompress, allowing a malicious RDP server to trigger a heap out-of-bounds write with attacker-controlled offset and content. This issue is fixed in version 3.27.1.
Which versions are affected by CVE-2026-55827?
It affects 1 product.
Linux distribution packages (29)
freerdp AlmaLinux:10 | All versions | 2:3.10.3-12.el10_2.7 |
freerdp-devel AlmaLinux:10 | All versions | 2:3.10.3-12.el10_2.7 |
freerdp-libs AlmaLinux:10 | All versions | 2:3.10.3-12.el10_2.7 |
freerdp-server AlmaLinux:10 | All versions | 2:3.10.3-12.el10_2.7 |
libwinpr AlmaLinux:10 | All versions | 2:3.10.3-12.el10_2.7 |
libwinpr-devel AlmaLinux:10 | All versions | 2:3.10.3-12.el10_2.7 |
freerdp Red Hat:enterprise_linux:10.2 | All versions | 2:3.10.3-12.el10_2.7 |
freerdp-debuginfo Red Hat:enterprise_linux:10.2 | All versions | 2:3.10.3-12.el10_2.7 |
freerdp-debugsource Red Hat:enterprise_linux:10.2 | All versions | 2:3.10.3-12.el10_2.7 |
freerdp-devel Red Hat:enterprise_linux:10.2 | All versions | 2:3.10.3-12.el10_2.7 |
freerdp-libs Red Hat:enterprise_linux:10.2 | All versions | 2:3.10.3-12.el10_2.7 |
freerdp-libs-debuginfo Red Hat:enterprise_linux:10.2 | All versions | 2:3.10.3-12.el10_2.7 |
freerdp-server Red Hat:enterprise_linux:10.2 | All versions | 2:3.10.3-12.el10_2.7 |
freerdp-server-debuginfo Red Hat:enterprise_linux:10.2 | All versions | 2:3.10.3-12.el10_2.7 |
libwinpr Red Hat:enterprise_linux:10.2 | All versions | 2:3.10.3-12.el10_2.7 |
libwinpr-debuginfo Red Hat:enterprise_linux:10.2 | All versions | 2:3.10.3-12.el10_2.7 |
libwinpr-devel Red Hat:enterprise_linux:10.2 | All versions | 2:3.10.3-12.el10_2.7 |
freerdp Red Hat:enterprise_linux_eus:10.0 | All versions | 2:3.10.3-3.el10_0.10 |
freerdp-debuginfo Red Hat:enterprise_linux_eus:10.0 | All versions | 2:3.10.3-3.el10_0.10 |
freerdp-debugsource Red Hat:enterprise_linux_eus:10.0 | All versions | 2:3.10.3-3.el10_0.10 |
freerdp-devel Red Hat:enterprise_linux_eus:10.0 | All versions | 2:3.10.3-3.el10_0.10 |
freerdp-libs Red Hat:enterprise_linux_eus:10.0 | All versions | 2:3.10.3-3.el10_0.10 |
freerdp-libs-debuginfo Red Hat:enterprise_linux_eus:10.0 | All versions | 2:3.10.3-3.el10_0.10 |
freerdp-server Red Hat:enterprise_linux_eus:10.0 | All versions | 2:3.10.3-3.el10_0.10 |
freerdp-server-debuginfo Red Hat:enterprise_linux_eus:10.0 | All versions | 2:3.10.3-3.el10_0.10 |
libwinpr Red Hat:enterprise_linux_eus:10.0 | All versions | 2:3.10.3-3.el10_0.10 |
libwinpr-debuginfo Red Hat:enterprise_linux_eus:10.0 | All versions | 2:3.10.3-3.el10_0.10 |
libwinpr-devel Red Hat:enterprise_linux_eus:10.0 | All versions | 2:3.10.3-3.el10_0.10 |
freerdp Rocky Linux:10 | All versions | 2:3.10.3-12.el10_2.7 |
Products include Freerdp Freerdp.
How do I fix CVE-2026-55827?
Upgrade to a fixed version.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-55827 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-55827 exists.
Other vulnerabilities in Freerdp Freerdp
- CVE-2021-37594 Other in n/a
- CVE-2021-37595 Other in n/a
- CVE-2026-67305 FreeRDP Windows Client before 3.29.0 Heap Buffer Overflow via Cliprdr
- CVE-2026-66402 FreeRDP before 3.29.0 TLS Certificate Identity Validation Bypass
- CVE-2026-67289 FreeRDP before 3.29.0 HTTP Proxy Request Injection via Redirection
Sources
Also known as ALSA-2026:50747, DEBIAN-CVE-2026-55827, GHSA-c495-h83v-3prp, RHSA-2026:50747, RHSA-2026:54667, RLSA-2026:50747 and 1 more.