CVE-2026-91948

high

Description

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.

References

https://www.vulncheck.com/advisories/freerdp-before-3.31.0-out-of-bounds-write-via-show-protocol

https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-9jcm-x588-gh26

https://github.com/FreeRDP/FreeRDP/commit/40d9202cd95551600c07437ce6bd5ecd7d31e57b

Details

Source: Mitre, NVD

Published: 2026-09-15

Updated: 2026-09-16

Risk Information

CVSS v2

Base Score: 7.1

Vector: CVSS2#AV:N/AC:H/Au:S/C:C/I:C/A:C

Severity: High

CVSS v3

Base Score: 7.5

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

Severity: High

CVSS v4

Base Score: 7.7

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

Severity: High

EPSS

EPSS: 0.00649