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Vulnerability record · CVE-2026-91948 · published 15 September 2026

CVE-2026-91948: FreeRDP versions before 3.31.0 contain an out-of-bounds write vulnerability in server-side static virtual chan…

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.

7.7 CVSS 4.0 High EPSS 0.59% · top 54.0% CWE-191 · CWE-191 Deferred
7.7CVSS 4.0 base score
0.59%EPSS exploitation probability, 30 days
NoNot in CISA KEV
0Affected product versions listed by NVD
3References
17 Sep 2026Last modified by NVD

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:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/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:

References

LinkTags
https://github.com/FreeRDP/FreeRDP/commit/40d9202cd95551600c07437ce6bd5ecd7d31e57b
https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-9jcm-x588-gh26
https://www.vulncheck.com/advisories/freerdp-before-3.31.0-out-of-bounds-write-via-show-protocol

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Source: NIST National Vulnerability Database (record CVE-2026-91948), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.