Amazon Linux 2 Security Advisory: ALAS2-2026-3199
Advisory Released Date: 2026-03-19
Advisory Updated Date: 2026-03-19
FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to version 3.23.0, a malicious RDP server can trigger a heap buffer overflow in FreeRDP clients using the GDI surface pipeline (e.g., `xfreerdp`) by sending an RDPGFX ClearCodec surface command with an out-of-bounds destination rectangle. The `gdi_SurfaceCommand_ClearCodec()` handler does not call `is_within_surface()` to validate the command rectangle against the destination surface dimensions, allowing attacker-controlled `cmd->left`/`cmd->top` (and subcodec rectangle offsets) to reach image copy routines that write into `surface->data` without bounds enforcement. The OOB write corrupts an adjacent `gdiGfxSurface` struct's `codecs*` pointer with attacker-controlled pixel data, and corruption of `codecs*` is sufficient to reach an indirect function pointer call (`NSC_CONTEXT.decode` at `nsc.c:500`) on a subsequent codec command -- full instruction pointer (RIP) control demonstrated in exploitability harness. Users should upgrade to version 3.23.0 to receive a patch. (CVE-2026-26955)
FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to version 3.23.0, in the RLE planar decode path, `planar_decompress_plane_rle()` writes into `pDstData` at `((nYDst+y) * nDstStep) + (4*nXDst) + nChannel` without verifying that `(nYDst+nSrcHeight)` fits in the destination height or that `(nXDst+nSrcWidth)` fits in the destination stride. When `TempFormat != DstFormat`, `pDstData` becomes `planar->pTempData` (sized for the desktop), while `nYDst` is only validated against the **surface** by `is_within_surface()`. A malicious RDP server can exploit this to perform a heap out-of-bounds write with attacker-controlled offset and pixel data on any connecting FreeRDP client. The OOB write reaches up to 132,096 bytes past the temp buffer end, and on the brk heap (desktop <= 128x128), an adjacent `NSC_CONTEXT` struct's `decode` function pointer is overwritten with attacker-controlled pixel data -- control-flow-relevant corruption (function pointer overwritten) demonstrated under deterministic heap layout (`nsc->decode = 0xFF414141FF414141`). Version 3.23.0 fixes the vulnerability. (CVE-2026-26965)
Affected Packages:
freerdp
Note:
This advisory is applicable to Amazon Linux 2 (AL2) Core repository. Visit this FAQ section for the difference between AL2 Core and AL2 Extras advisories.
Issue Correction:
Run yum update freerdp or yum update --advisory ALAS2-2026-3199 to update your system.
aarch64:
freerdp-2.11.7-1.amzn2.0.6.aarch64
freerdp-libs-2.11.7-1.amzn2.0.6.aarch64
freerdp-devel-2.11.7-1.amzn2.0.6.aarch64
libwinpr-2.11.7-1.amzn2.0.6.aarch64
libwinpr-devel-2.11.7-1.amzn2.0.6.aarch64
freerdp-debuginfo-2.11.7-1.amzn2.0.6.aarch64
i686:
freerdp-2.11.7-1.amzn2.0.6.i686
freerdp-libs-2.11.7-1.amzn2.0.6.i686
freerdp-devel-2.11.7-1.amzn2.0.6.i686
libwinpr-2.11.7-1.amzn2.0.6.i686
libwinpr-devel-2.11.7-1.amzn2.0.6.i686
freerdp-debuginfo-2.11.7-1.amzn2.0.6.i686
src:
freerdp-2.11.7-1.amzn2.0.6.src
x86_64:
freerdp-2.11.7-1.amzn2.0.6.x86_64
freerdp-libs-2.11.7-1.amzn2.0.6.x86_64
freerdp-devel-2.11.7-1.amzn2.0.6.x86_64
libwinpr-2.11.7-1.amzn2.0.6.x86_64
libwinpr-devel-2.11.7-1.amzn2.0.6.x86_64
freerdp-debuginfo-2.11.7-1.amzn2.0.6.x86_64