High severity · published Mar 30, 2026
CVE-2026-33986
FreeRDP: H.264 YUV Buffer Dimension Desync - Heap OOB Write
7.5
CVSS
0.3%
EPSS
No
On KEV
Description
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.
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
Attack vector
Network
Complexity
High
Privileges
None
User interaction
Required
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.3% · higher than 19% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
FR
FreeRDP · FreeRDP
< 3.24.2 · source: vendor, NVD
RH
Red Hat Enterprise Linux 6 · Red Hat
All versions, or not specified · source: CISA
RH
Red Hat Enterprise Linux 7 · Red Hat
All versions, or not specified · source: CISA
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-33986
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-33986
Patch
https://github.com/FreeRDP/FreeRDP/commit/f6e43e208958140074ae9bb93cd0c9045a371c77
Patch
https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-h6qw-wxvm-hf97
access.redhat.com
https://access.redhat.com/security/cve/CVE-2026-33986
bugzilla.redhat.com
https://bugzilla.redhat.com/show_bug.cgi?id=2453221
security.access.redhat.com
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-33986.json
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