CVE-2026-55193

FreeRDP: Heap-buffer-overflow write in TS Gateway RPC fragment receive due to uncapped bind_ack max_xmit_frag

HIGH
8.8
CVSS Score
Published: August 19, 2026 at 05:46 PM UTC
Updated: October 26, 2026 at 11:10 AM UTC
1 product affected across 1 vendorFreeRDP

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Severity
HIGH8.8
Exploit prediction
EPSS 0.5%
SSVC
PoC

Description

FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.27.0, FreeRDP clients using TS Gateway accept a server-controlled max_xmit_frag value in libfreerdp/core/gateway/rpc_bind.c without bounding it to the 4088-byte ReceiveFragment allocation. A malicious gateway can advertise 65535 and then send a response fragment of the same length, causing rpc_channel_read in libfreerdp/core/gateway/rpc.c to write up to 65535 bytes into the smaller ReceiveFragment buffer. This can crash the client and may permit code execution through attacker-controlled heap corruption. This issue is fixed in version 3.27.0.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 3.27.0
Affected range stops below 3.27.0, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (4)

x_refsource_CONFIRMExploitVendor Advisory
Source: cverecord
https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-7rp4-66mc-j9vx
x_refsource_MISCIssue TrackingPatch
Source: cverecord
https://github.com/FreeRDP/FreeRDP/pull/12873
x_refsource_MISCRelease Notes
Source: cverecord
https://github.com/FreeRDP/FreeRDP/releases/tag/3.27.0

SSVC — Action Prioritization

SSVCPoCNot automatableTotal impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
HIGH
Vector?

Quick Info

StatusANALYZED
CWE
CWE-122

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