CVE-2026-91948 PUBLISHED

FreeRDP before 3.31.0 Out-of-bounds Write via SHOW_PROTOCOL

Assigner: VulnCheck
Reserved: 15.09.2026 Published: 15.09.2026 Updated: 16.09.2026

FreeRDP versions before 3.31.0 contain an out-of-bounds write vulnerability in server-side static virtual channel handling when CHANNEL_OPTION_SHOW_PROTOCOL is enabled. Authenticated clients can queue oversized channel messages that cause buffer underflow and corrupt heap memory including live pointers, potentially enabling code execution.

CVSS Vector: CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
CVSS Score: 7.7

Exploitability Metrics		Vulnerable System Impact Metrics		Subsequent System Impact Metrics
Attack Vector	Network	Confidentiality	High	Confidentiality	None
Attack Complexity	High	Integrity	High	Integrity	None
Attack Requirements	Present	Availability	High	Availability	None
Privileges Required	Low
User Interaction	None

CVSS 4.0

CVSS Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
CVSS Score: 7.5

Attack Vector	Network	Scope	Unchanged
Attack Complexity	High	Confidentiality Impact	High
Privileges Required	Low	Integrity Impact	High
User Interaction	None	Availability Impact	High

CVSS 3.1

Product Status

Vendor	FreeRDP
Product	FreeRDP
Versions	Default: unaffected affected from 3.28.0 to 3.31.0 (excl.) Version 3.31.0 is unaffected

CVE-2026-91948 PUBLISHED

FreeRDP before 3.31.0 Out-of-bounds Write via SHOW_PROTOCOL

Metrics

Product Status

Credits

References

Problem Types