CVE-2026-26965

NameCVE-2026-26965
DescriptionFreeRDP 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.
SourceCVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
freerdp2 (PTS)bullseye2.3.0+dfsg1-2+deb11u1vulnerable
bullseye (security)2.3.0+dfsg1-2+deb11u3vulnerable
bookworm2.11.7+dfsg1-6~deb12u1vulnerable
freerdp3 (PTS)trixie3.15.0+dfsg-2.1vulnerable
forky3.23.0+dfsg-1fixed
sid3.24.1+dfsg-1fixed

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
freerdp2source(unstable)(unfixed)
freerdp3source(unstable)3.23.0+dfsg-1

Notes

[trixie] - freerdp3 <no-dsa> (Minor issue)
[bookworm] - freerdp3 <no-dsa> (Minor issue)
[bookworm] - freerdp2 <no-dsa> (Minor issue)
https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-5vgf-mw4f-r33h
Fixed by: https://github.com/FreeRDP/FreeRDP/commit/a0be5cb87d760bb1c803ad1bb835aa1e73e62abc (3.23.0)

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