FreeRDP has Out-of-bounds Write
21Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 8.8epss 0.6%
exploitation probability
0.6%top 53% of all CVEs
observed exploitation
nono source reports it
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 ≤ 128×128), 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.
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Affected products
FreeRDP · FreeRDPReferences
https://access.redhat.com/errata/RHSA-2026:19033https://access.redhat.com/errata/RHSA-2026:5936https://access.redhat.com/errata/RHSA-2026:5939https://access.redhat.com/errata/RHSA-2026:6004https://access.redhat.com/errata/RHSA-2026:6005https://access.redhat.com/errata/RHSA-2026:6384https://access.redhat.com/errata/RHSA-2026:6385https://access.redhat.com/errata/RHSA-2026:6395https://access.redhat.com/errata/RHSA-2026:6396https://access.redhat.com/errata/RHSA-2026:6616https://access.redhat.com/errata/RHSA-2026:6665https://access.redhat.com/errata/RHSA-2026:6712