High severity · published Sep 15, 2026
CVE-2026-91948
FreeRDP before 3.31.0 Out-of-bounds Write via SHOW_PROTOCOL
7.5
CVSS
0.6%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Attack vector
Network
Complexity
High
Privileges
Low
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.6% · higher than 48% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
FR
FreeRDP · FreeRDP
3.28.0 before 3.31.0 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-91948
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-91948
github.com
https://github.com/FreeRDP/FreeRDP/commit/40d9202cd95551600c07437ce6bd5ecd7d31e57b
github.com
https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-9jcm-x588-gh26
www.vulncheck.com
https://www.vulncheck.com/advisories/freerdp-before-3.31.0-out-of-bounds-write-via-show-protocol
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