CVE-2026-33984 HIGH

CVE-2026-33984: FreeRDP: ClearCodec resize_vbar_entry() Heap OOB Write

Vendor Freerdp
Product FreeRDP
Weakness CWE-122
Published March 30, 2026
Last update June 30, 2026

CVSS base score

7.5/10
Attack vector Network
Attack complexity High
Privileges required None
User interaction Required
Confidentiality High
Integrity High

CVSS vector

CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H

What the vulnerability does

01Description

FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to version 3.24.2, in resize_vbar_entry() in libfreerdp/codec/clear.c, vBarEntry->size is updated to vBarEntry->count before the winpr_aligned_recalloc() call. If realloc fails, size is inflated while pixels still points to the old, smaller buffer. On a subsequent call where count <= size (the inflated value), realloc is skipped. The caller then writes count * bpp bytes of attacker-controlled pixel data into the undersized buffer, causing a heap buffer overflow. This issue has been patched in version 3.24.2.

Key dates

02Disclosure timeline

March 30, 2026 CVE published
June 30, 2026 Record updated