CVE-2026-33984
Heap Buffer Overflow in FreeRDP clear.c Causes Memory Corruption
Publication date: 2026-03-30
Last updated on: 2026-04-01
Assigner: GitHub, Inc.
Description
Description
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| freerdp | freerdp | to 3.24.2 (exc) |
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| CWE-122 | A heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc(). |
| CWE-131 | The product does not correctly calculate the size to be used when allocating a buffer, which could lead to a buffer overflow. |
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?
This vulnerability exists in FreeRDP, a free implementation of the Remote Desktop Protocol, in versions prior to 3.24.2. The issue occurs in the function resize_vbar_entry() within the file libfreerdp/codec/clear.c. Specifically, the size field of a vBarEntry structure is updated before a memory reallocation call (winpr_aligned_recalloc). If this reallocation fails, the size remains inflated while the pixel buffer still points to the smaller, original memory area. On subsequent calls where the count is less than or equal to this inflated size, the reallocation is skipped, leading to a situation where attacker-controlled pixel data is written beyond the bounds of the allocated buffer. This causes a heap buffer overflow.
How can this vulnerability impact me? :
The heap buffer overflow caused by this vulnerability can lead to serious security impacts. According to the CVSS score of 7.5, it has high severity with potential consequences including confidentiality, integrity, and availability impacts. An attacker could exploit this flaw to execute arbitrary code, cause a denial of service, or corrupt memory, potentially compromising the affected system.
What immediate steps should I take to mitigate this vulnerability?
The vulnerability has been patched in FreeRDP version 3.24.2. To mitigate this vulnerability, you should update FreeRDP to version 3.24.2 or later.