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Freerdp CVE-2026-33984

| EUVDEUVD-2026-17229 HIGH
Heap-based Buffer Overflow (CWE-122)
2026-03-30 GitHub_M
Heap Overflow Buffer Overflow Freerdp
7.5
CVSS 3.1 · Vendor: GitHub_M
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Severity by source

Vendor (GitHub_M) PRIMARY
7.5 HIGH
AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
Ubuntu
MEDIUM
qualitative
SUSE
HIGH
qualitative
Red Hat
7.5 HIGH
qualitative

Primary rating from Vendor (GitHub_M).

CVSS VectorVendor: GitHub_M

CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

Lifecycle Timeline

4
Patch released
Mar 31, 2026 - 21:13 nvd
Patch available
EUVD ID Assigned
Mar 30, 2026 - 22:15 euvd
EUVD-2026-17229
Analysis Generated
Mar 30, 2026 - 22:15 vuln.today
CVE Published
Mar 30, 2026 - 21:42 nvd
HIGH 7.5

DescriptionCVE.org

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.

AnalysisAI

Heap buffer overflow in FreeRDP's CLEAR codec implementation allows remote attackers to execute arbitrary code when processing malicious RDP server responses. Affects all FreeRDP versions prior to 3.24.2. Attack requires high complexity and user interaction (victim must connect to attacker-controlled RDP server), but no authentication is required. CVSS 7.5 reflects the network-accessible attack vector with potential for complete system compromise. No public exploit identified at time of analysis, though technical details are publicly disclosed via GitHub security advisory.

Technical ContextAI

FreeRDP is an open-source implementation of Microsoft's Remote Desktop Protocol (RDP), widely used in Linux environments and cross-platform remote access solutions. The vulnerability resides in libfreerdp/codec/clear.c within the resize_vbar_entry() function, which handles decompression of CLEAR codec data streams used for screen updates in RDP sessions. The flaw is a classic use-after-reallocation error (CWE-122: Heap-based Buffer Overflow) where the vBarEntry->size field is prematurely updated before confirming successful memory reallocation via winpr_aligned_recalloc(). When realloc fails, the size field reflects the requested larger allocation while the pixels pointer still references the original smaller buffer. Subsequent operations that check count against the inflated size value skip reallocation and proceed to write attacker-controlled pixel data beyond buffer boundaries. This violates memory safety assumptions in the CLEAR codec parser, which processes compressed bitmap data transmitted during RDP screen refresh operations.

RemediationAI

Vendor-released patch: FreeRDP 3.24.2 resolves this vulnerability via commit dc7fdb165095139be779a4000199bc1706b06ad5 available at https://github.com/FreeRDP/FreeRDP/commit/dc7fdb165095139be779a4000199bc1706b06ad5. Organizations should immediately upgrade all FreeRDP installations to version 3.24.2 or later using distribution package managers (apt upgrade freerdp2-x11 for Debian/Ubuntu) or by building from patched source. For environments where immediate patching is not feasible, implement strict controls on RDP server trust: enforce organizational policies prohibiting connections to untrusted RDP servers, deploy network egress filtering to block outbound RDP connections except to explicitly whitelisted internal servers, and consider application whitelisting to prevent unauthorized RDP client usage. Monitor security advisories from Ubuntu and Debian for distribution-specific patched package availability. No effective configuration-based workaround exists as the flaw is in core codec processing logic.

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Same weakness CWE-122 – Heap-based Buffer Overflow

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Same technique Heap Overflow

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CVE-2025-5419 HIGH POC
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8.4
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9.2
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9.3
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CVE-2024-30038 HIGH POC
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Vendor StatusVendor

Ubuntu

Priority: Medium
freerdp
Release Status Version
xenial needs-triage -
bionic needs-triage -
jammy DNE -
noble DNE -
questing DNE -
upstream needs-triage -
freerdp2
Release Status Version
bionic needs-triage -
focal needs-triage -
jammy needs-triage -
noble needs-triage -
questing DNE -
upstream needs-triage -
freerdp3
Release Status Version
jammy DNE -
noble needs-triage -
questing needs-triage -
upstream needs-triage -

Debian

freerdp2
Release Status Fixed Version Urgency
bullseye vulnerable 2.3.0+dfsg1-2+deb11u1 -
bullseye (security) vulnerable 2.3.0+dfsg1-2+deb11u3 -
bookworm vulnerable 2.11.7+dfsg1-6~deb12u1 -
(unstable) fixed (unfixed) -
freerdp3
Release Status Fixed Version Urgency
trixie vulnerable 3.15.0+dfsg-2.1 -
forky, sid fixed 3.24.2+dfsg-1 -
(unstable) fixed 3.24.2+dfsg-1 -

SUSE

Severity: High
Product Status
SUSE Liberty Linux 10 Fixed
SUSE Liberty Linux 9 Fixed
SUSE Linux Enterprise Desktop 15 SP7 Fixed
SUSE Linux Enterprise Desktop 15 SP7 Fixed
SUSE Linux Enterprise Module for Package Hub 15 SP7 Fixed

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CVE-2026-33984 vulnerability details – vuln.today
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