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Fencer Vulns
high 7.5

CVE-2026-91948 json

FreeRDP before 3.31.0 Out-of-bounds Write via SHOW_PROTOCOL

published 2026-09-15 55 d ago modified 2026-09-17 53 d ago also EUVD-2026-78805

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.6%
EPSS 0.6% chance of exploitation in 30 days, percentile 48%
public exploits
0
none known

Summary

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.

Patch / fix

  • FreeRDP FreeRDP 3.31.0
  • freerdp3 Debian 14 3.31.0+dfsg-1

debian advisories DEBIAN-CVE-2026-91948

  • freerdp3 Ubuntu 24.04 LTS 3.31.0+dfsg-0ubuntu0.24.04.1
  • freerdp3 Ubuntu 26.04 LTS 3.31.0+dfsg-0ubuntu0.26.04.1

ubuntu advisories UBUNTU-CVE-2026-91948

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-91948 updated cvss 7.5

FreeRDP: FreeRDP: Arbitrary code execution via oversized channel messages in SHOW_PROTOCOL

  • Red Hat Enterprise Linux 10 freerdp
    affected: workaround, no fix available
  • Red Hat Enterprise Linux 6 freerdp, freerdp-libs, freerdp-plugins Red Hat Enterprise Linux 7 freerdp, libwinpr, freerdp-libs, freerdp-plugins Red Hat Enterprise Linux 8 freerdp, libwinpr, freerdp-libs Red Hat Enterprise Linux 9 freerdp, libwinpr, freerdp-libs
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
54 d ago

Exploit prediction

0.59% chance of exploitation in the next 30 days, higher than 48% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 4.0 7.7 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
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
CNA 4.0 7.7 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:X/V:X/RE:X/U:X

Affected products

  • FreeRDP FreeRDP

Classification

Weakness
  • CWE-191 Integer Underflow (Wrap or Wraparound)

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.