FreeRDP <3.24.2 h264 Buffer Use-After-Free: premature width/height update
CVE-2026-33986 Published on March 30, 2026
FreeRDP: H.264 YUV Buffer Dimension Desync - Heap OOB Write
FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to version 3.24.2, in yuv_ensure_buffer() in libfreerdp/codec/h264.c, h264->width and h264->height are updated before the reallocation loop. If any winpr_aligned_recalloc() call fails, the function returns FALSE but width/height are already inflated. This issue has been patched in version 3.24.2.
Vulnerability Analysis
CVE-2026-33986 is exploitable with network access, requires user interaction. This vulnerability is consided to have a high level of attack complexity. The potential impact of an exploit of this vulnerability is considered to be very high.
Weakness Types
Heap-based Buffer Overflow
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().
Incorrect Calculation of Buffer Size
The software does not correctly calculate the size to be used when allocating a buffer, which could lead to a buffer overflow.
Products Associated with CVE-2026-33986
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Affected Versions
FreeRDP Version < 3.24.2 is affected by CVE-2026-33986Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.