CVE-2026-55193 FreeRDP: Heap-buffer-overflow write in TS Gateway RPC fragment receive due to uncapped bind_ack max_xmit_frag
A heap-buffer-overflow in FreeRDP allows a malicious gateway to crash the client or execute code via crafted RPC fragments.
- 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-2026-55193?
CVE-2026-55193 is a high-severity memory corruption vulnerability in Freerdp Freerdp, published on 19 Aug 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 3.27.0, FreeRDP clients using TS Gateway accept a server-controlled max_xmit_frag value in libfreerdp/core/gateway/rpc_bind.c without bounding it to the 4088-byte ReceiveFragment allocation. A malicious gateway can advertise 65535 and then send a response fragment of the same length, causing rpc_channel_read in libfreerdp/core/gateway/rpc.c to write up to 65535 bytes into the smaller ReceiveFragment buffer. This can crash the client and may permit code execution through attacker-controlled heap corruption. This issue is fixed in version 3.27.0.
Weakness: CWE-122
Which versions are affected by CVE-2026-55193?
It affects 1 product.
Linux distribution packages (40)
freerdp AlmaLinux:10 | All versions | 2:3.10.3-12.el10_2.11 |
freerdp-devel AlmaLinux:10 | All versions | 2:3.10.3-12.el10_2.11 |
freerdp-libs AlmaLinux:10 | All versions | 2:3.10.3-12.el10_2.11 |
freerdp-server AlmaLinux:10 | All versions | 2:3.10.3-12.el10_2.11 |
libwinpr AlmaLinux:10 | All versions | 2:3.10.3-12.el10_2.11 |
libwinpr-devel AlmaLinux:10 | All versions | 2:3.10.3-12.el10_2.11 |
freerdp AlmaLinux:8 | All versions | 2:2.11.7-13.el8_10 |
freerdp-devel AlmaLinux:8 | All versions | 2:2.11.7-13.el8_10 |
freerdp-libs AlmaLinux:8 | All versions | 2:2.11.7-13.el8_10 |
libwinpr AlmaLinux:8 | All versions | 2:2.11.7-13.el8_10 |
libwinpr-devel AlmaLinux:8 | All versions | 2:2.11.7-13.el8_10 |
freerdp AlmaLinux:9 | All versions | 2:2.11.7-7.el9_8.7 |
freerdp-devel AlmaLinux:9 | All versions | 2:2.11.7-7.el9_8.7 |
freerdp-libs AlmaLinux:9 | All versions | 2:2.11.7-7.el9_8.7 |
libwinpr AlmaLinux:9 | All versions | 2:2.11.7-7.el9_8.7 |
libwinpr-devel AlmaLinux:9 | All versions | 2:2.11.7-7.el9_8.7 |
freerdp Red Hat:enterprise_linux:10.2 | All versions | 2:3.10.3-12.el10_2.11 |
freerdp-debuginfo Red Hat:enterprise_linux:10.2 | All versions | 2:3.10.3-12.el10_2.11 |
freerdp-debugsource Red Hat:enterprise_linux:10.2 | All versions | 2:3.10.3-12.el10_2.11 |
freerdp-devel Red Hat:enterprise_linux:10.2 | All versions | 2:3.10.3-12.el10_2.11 |
freerdp-libs Red Hat:enterprise_linux:10.2 | All versions | 2:3.10.3-12.el10_2.11 |
freerdp-libs-debuginfo Red Hat:enterprise_linux:10.2 | All versions | 2:3.10.3-12.el10_2.11 |
freerdp-server Red Hat:enterprise_linux:10.2 | All versions | 2:3.10.3-12.el10_2.11 |
freerdp-server-debuginfo Red Hat:enterprise_linux:10.2 | All versions | 2:3.10.3-12.el10_2.11 |
libwinpr Red Hat:enterprise_linux:10.2 | All versions | 2:3.10.3-12.el10_2.11 |
libwinpr-debuginfo Red Hat:enterprise_linux:10.2 | All versions | 2:3.10.3-12.el10_2.11 |
libwinpr-devel Red Hat:enterprise_linux:10.2 | All versions | 2:3.10.3-12.el10_2.11 |
freerdp Red Hat:enterprise_linux:8::appstream | All versions | 2:2.11.7-13.el8_10 |
freerdp-debuginfo Red Hat:enterprise_linux:8::appstream | All versions | 2:2.11.7-13.el8_10 |
freerdp-debugsource Red Hat:enterprise_linux:8::appstream | All versions | 2:2.11.7-13.el8_10 |
freerdp-libs Red Hat:enterprise_linux:8::appstream | All versions | 2:2.11.7-13.el8_10 |
freerdp-libs-debuginfo Red Hat:enterprise_linux:8::appstream | All versions | 2:2.11.7-13.el8_10 |
libwinpr Red Hat:enterprise_linux:8::appstream | All versions | 2:2.11.7-13.el8_10 |
libwinpr-debuginfo Red Hat:enterprise_linux:8::appstream | All versions | 2:2.11.7-13.el8_10 |
libwinpr-devel Red Hat:enterprise_linux:8::appstream | All versions | 2:2.11.7-13.el8_10 |
freerdp-debuginfo Red Hat:enterprise_linux:8::crb | All versions | 2:2.11.7-13.el8_10 |
freerdp-debugsource Red Hat:enterprise_linux:8::crb | All versions | 2:2.11.7-13.el8_10 |
freerdp-devel Red Hat:enterprise_linux:8::crb | All versions | 2:2.11.7-13.el8_10 |
freerdp-libs-debuginfo Red Hat:enterprise_linux:8::crb | All versions | 2:2.11.7-13.el8_10 |
libwinpr-debuginfo Red Hat:enterprise_linux:8::crb | All versions | 2:2.11.7-13.el8_10 |
Products include Freerdp Freerdp.
How do I fix CVE-2026-55193?
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-2026-55193 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-55193 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-2026:66347, ALSA-2026:66349, ALSA-2026:69387, CLSA-2026-1792767913, CLSA-2026-1792768177, DEBIAN-CVE-2026-55193 and 19 more.