CVE-2026-67306: FreeRDP before 3.29.0 Out-of-Bounds Read via Planar RLE
FreeRDP versions 3.28.0 and earlier contain an out-of-bounds read vulnerability in the RDP6 planar RLE bitmap decoder functions planardecompressplanerle and planardecompressplanerleonly in libfreerdp/codec/planar.c. Only the 1-byte control byte is bounds-checked; the subsequent 0–15 attacker-declared raw bytes are read without validating that the source buffer contains them. A malicious or compromised RDP server can send a truncated planar-encoded bitmap or surface update (reachable via both the Bitmap Update PDU and RDPGFX Surface Command paths) that causes the client to read past the end of the source buffer. The issue is fixed in FreeRDP 3.29.0.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
FreeRDPto a version that resolves this vulnerability.Fixed in 3.29.0 - Configuration
Upgrade FreeRDP to 3.29.0 to fix the out-of-bounds read in planar_decompress_plane_rle and planar_decompress_plane_rle_only (libfreerdp/codec/planar.c); until upgraded, avoid/disable planar RLE decoding paths handling truncated planar-encoded bitmap/surface updates over Bitmap Update PDU and RDPGFX Surface Command.
FreeRDP RDP client paths (Bitmap Update PDU and RDPGFX Surface Command) RDPGFX/Bitmap Update handling of planar-encoded bitmaps = disable affected planar-encoded planar RLE decoding until upgraded
Event History
Frequently Asked Questions
What is the severity of CVE-2026-67306?
The severity of CVE-2026-67306 is medium with a score of 5.4.
How do I fix CVE-2026-67306?
To fix CVE-2026-67306, upgrade to FreeRDP version 3.29.0 or later.
What type of vulnerability is CVE-2026-67306?
CVE-2026-67306 is an out-of-bounds read vulnerability in FreeRDP.
Which versions of FreeRDP are affected by CVE-2026-67306?
FreeRDP versions 3.28.0 and earlier are affected by CVE-2026-67306.
What components are involved in CVE-2026-67306?
CVE-2026-67306 involves the RDP6 planar RLE bitmap decoder functions in libfreerdp.