What is CVE-2026-91948?

CVE-2026-91948 is a high-severity vulnerability in Freerdp, classified under Integer Underflow. CVSS score: 7.5/10. Published 2026-09-15.

How severe is CVE-2026-91948?

High severity. CVSS v3 base score is 7.5 out of 10.

Integer overflow in Freerdp

CVE-2026-91948

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.

Published 2026-09-15 · last modified 2026-09-17.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.006 (48.1th percentile), scored 2026-10-30.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 48th percentile — 48.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.006 · newest: 0.006 · change: 0.000

Affected products

Freerdp

Weakness classification (CWE)

CWE-191 — Integer Underflow

References

github.com/FreeRDP/FreeRDP/security/advisories/GHSA-9jcm-x588-gh26 (vendor-advisory)
github.com/FreeRDP/FreeRDP/commit/40d9202cd95551600c07437ce6bd5ecd7d31e57b (patch)
www.vulncheck.com/advisories/freerdp-before-3.31.0-out-of-bounds-write-via-show… (third-party-advisory)

Frequently asked questions

What is CVE-2026-91948?: CVE-2026-91948 is a high-severity vulnerability in Freerdp, classified under Integer Underflow. CVSS score: 7.5/10. Published 2026-09-15.
How severe is CVE-2026-91948?: High severity. CVSS v3 base score is 7.5 out of 10.