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FreeRDP CVE-2026-55191

| EUVDEUVD-2026-62660 HIGH
Heap-based Buffer Overflow (CWE-122)
N/A vendor:alpine
8.7
CVSS 4.0 · Vendor: vendor:alpine
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Vendor (vendor:alpine) PRIMARY
8.7 HIGH
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
vuln.today AI
8.8 HIGH

Network-reachable client-side flaw; no attacker privileges needed; user must initiate connection (UI:R); heap overflow enables full compromise of the client process.

3.1 AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
4.0 AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

Primary rating from Vendor (vendor:alpine).

CVSS VectorVendor: vendor:alpine

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
P
Scope
X

Lifecycle Timeline

6
Patch available
Aug 19, 2026 - 19:18 EUVD
Source Code Evidence Fetched
Aug 19, 2026 - 18:35 vuln.today
Analysis Updated
Aug 19, 2026 - 18:35 vuln.today
v2 (cvss_changed)
Re-analysis Queued
Aug 19, 2026 - 18:22 vuln.today
cvss_changed
CVSS changed
Aug 19, 2026 - 18:22 NVD
8.7 (HIGH)
Analysis Generated
Jun 29, 2026 - 13:30 vuln.today

DescriptionCVE.org

Alpine Linux: freerdp fixed in 3.27.1-r0

AnalysisAI

Heap-based buffer overflow in FreeRDP's AVC444/H264 codec allows a malicious RDP server to achieve remote code execution on connecting clients. The flaw resides in the avc444_ensure_buffer function in libfreerdp/codec/h264.c, where stride-height multiplication was performed without overflow guards, enabling an integer overflow to produce an undersized heap allocation followed by an out-of-bounds write. …

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Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata

Recon
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Exploit
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Install
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C2
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Execute
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Vulnerability AssessmentAI

Exploitation The FreeRDP client must negotiate and use AVC444 (H264-based RemoteFX) graphics mode with the RDP server - this is the codec path containing the vulnerable function. … Additional conditions and limiting factors are described in the full assessment.
Risk Assessment The CVSS 4.0 vector (AV:N/AC:L/AT:N/PR:N/UI:P) places this at 8.7, reflecting low attack complexity and no required privileges on the attacker side, with only passive user interaction (the victim must connect). … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in.
Exploit Scenario Full exploit scenario with step-by-step reproduction available after sign-in.
Remediation The primary fix is upgrading FreeRDP to upstream version 3.27.0 or later (https://github.com/FreeRDP/FreeRDP/releases/tag/3.27.0). … Detailed patch versions, workarounds, and compensating controls in full report.

Recommended ActionAI

Within 24 hours, inventory all endpoints running FreeRDP and classify exposure based on whether they connect to untrusted or external RDP servers; immediately restrict RDP connections to authenticated internal servers only through firewall and network segmentation policies. …

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CVE-2026-55191 vulnerability details – vuln.today

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