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Fencer Vulns
medium 6.5

CVE-2026-31883 json

FreeRDP has a `size_t` underflow in ADPCM decoder leads to heap-buffer-overflow write

published 2026-03-13 7 mo ago modified 2026-06-17 4 mo ago also EUVD-2026-12061

cvss
6.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 29%
public exploits
0
none known

Summary

FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.24.0, a size_t underflow in the IMA-ADPCM and MS-ADPCM audio decoders leads to heap-buffer-overflow write via the RDPSND audio channel. In libfreerdp/codec/dsp.c, the IMA-ADPCM and MS-ADPCM decoders subtract block header sizes from a size_t variable without checking for underflow. When nBlockAlign (received from the server) is set such that size % block_size == 0 triggers the header parsing at a point where size is smaller than the header (4 or 8 bytes), the subtraction wraps size to ~SIZE_MAX. The while (size > 0) loop then continues for an astronomical number of iterations. This vulnerability is fixed in 3.24.0.

Patch / fix

  • freerdp freerdp 3.24.0
  • freerdp3 Debian 13 3.15.0+dfsg-2.1+deb13u2
  • freerdp3 Debian 14 3.24.0+dfsg-1

debian advisories DEBIAN-CVE-2026-31883

  • freerdp3 Ubuntu 24.04 LTS 3.30.0+dfsg-0ubuntu0.24.04.1

ubuntu advisories UBUNTU-CVE-2026-31883

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

  • freerdp RHEL 9 2:2.11.7-7.el9_8.3
  • libwinpr RHEL 9 2:2.11.7-7.el9_8.3
  • freerdp-libs RHEL 9 2:2.11.7-7.el9_8.3
  • freerdp RHEL 10.2 2:3.10.3-12.el10_2.5
  • libwinpr RHEL 10.2 2:3.10.3-12.el10_2.5
  • freerdp-libs RHEL 10.2 2:3.10.3-12.el10_2.5
  • freerdp-server RHEL 10.2 2:3.10.3-12.el10_2.5
  • freerdp RHEL 9 2:2.11.7-1.el9_7.7

red hat advisories RHSA-2026:20605RHSA-2026:20546RHSA-2026:19811RHSA-2026:19358RHSA-2026:19142RHSA-2026:16866

  • freerdp SLE Workstation Extension 15 SP7, SLE Module for Package Hub 15 SP7 3.10.3-150700.3.9.1
  • freerdp2 SLE Workstation Extension 15 SP7, SLE Module for Package Hub 15 SP7 2.11.7-150700.3.14.1
  • freerdp SLE Module for Package Hub 15 SP7, openSUSE Leap 15.6 2.11.2-150600.4.18.1
  • freerdp SLE Module for Package Hub 15 SP7 2.4.0-150400.3.47.1
  • freerdp SLES LTSS Extended Security 12 SP5, SLES 12 SP5-LTSS 2.1.2-12.63.1

suse advisories SUSE-SU-2026:1398-1SUSE-SU-2026:1165-1SUSE-SU-2026:1164-1SUSE-SU-2026:1160-1SUSE-SU-2026:1129-1

  • freerdp2 openSUSE Tumbleweed 2.11.7-6.1
  • freerdp openSUSE Tumbleweed 3.24.1-1.1

opensuse advisories openSUSE-SU-2026:10459-1openSUSE-SU-2026:10408-1

  • freerdp AlmaLinux 9 2:2.11.7-7.el9_8.3
  • libwinpr AlmaLinux 9 2:2.11.7-7.el9_8.3
  • freerdp-libs AlmaLinux 9 2:2.11.7-7.el9_8.3
  • freerdp AlmaLinux 9 2:2.11.7-1.el9_7.7
  • libwinpr AlmaLinux 9 2:2.11.7-1.el9_7.7
  • freerdp-libs AlmaLinux 9 2:2.11.7-1.el9_7.7
  • freerdp AlmaLinux 10 2:3.10.3-5.el10_1.8
  • libwinpr AlmaLinux 10 2:3.10.3-5.el10_1.8

almalinux advisories ALSA-2026:19358ALSA-2026:16482ALSA-2026:16014ALSA-2026:16019

  • freerdp Rocky Linux 10 2:3.10.3-12.el10_2.5
  • freerdp Rocky Linux 9 2:2.11.7-7.el9_8.3
  • freerdp Rocky Linux 9 2:2.11.7-1.el9_7.7
  • freerdp Rocky Linux 10 2:3.10.3-5.el10_1.8
  • freerdp Rocky Linux 8 2:2.11.7-9.el8_10

rocky linux advisories RLSA-2026:19142RLSA-2026:19358RLSA-2026:16482RLSA-2026:16014RLSA-2026:16019

  • freerdp Alpine 3.24, Alpine 3.23 3.24.0-r0

alpine advisories ALPINE-CVE-2026-31883

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org 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-2026-31883 updated cvss 7.3

freerdp: FreeRDP: Denial of Service via crafted audio data in RDP

  • Red Hat Enterprise Linux 6 freerdp, freerdp-libs, freerdp-plugins
    affected: no fix planned “Will not fix”
  • Red Hat CodeReady Linux Builder EUS (v.9.4) freerdp-devel 2.11.2-1.el9_4.8, libwinpr-devel 2.11.2-1.el9_4.8, freerdp-debuginfo 2.11.2-1.el9_4.8, libwinpr-debuginfo 2.11.2-1.el9_4.8, freerdp-debugsource 2.11.2-1.el9_4.8, freerdp-libs-debuginfo 2.11.2-1.el9_4.8
    fixed: vendor fix RHSA-2026:16866
  • Red Hat CodeReady Linux Builder EUS (v.9.6) freerdp-devel 2.11.7-1.el9_6.10, libwinpr-devel 2.11.7-1.el9_6.10, freerdp-debuginfo 2.11.7-1.el9_6.10, libwinpr-debuginfo 2.11.7-1.el9_6.10, freerdp-debugsource 2.11.7-1.el9_6.10, freerdp-libs-debuginfo 2.11.7-1.el9_6.10
    fixed: vendor fix RHSA-2026:16865
  • Red Hat Enterprise Linux AppStream (v. 8) freerdp 2.11.7-9.el8_10, libwinpr 2.11.7-9.el8_10, freerdp-libs 2.11.7-9.el8_10
    fixed: vendor fix RHSA-2026:16019
  • Red Hat Enterprise Linux AppStream (v. 9) freerdp 2.11.7-1.el9_7.7, freerdp 2.11.7-7.el9_8.3, libwinpr 2.11.7-1.el9_7.7, libwinpr 2.11.7-7.el9_8.3, freerdp-libs 2.11.7-1.el9_7.7, freerdp-libs 2.11.7-7.el9_8.3
    fixed: vendor fix RHSA-2026:16482
  • Red Hat Enterprise Linux AppStream (v. 10) freerdp 3.10.3-5.el10_1.8, freerdp 3.10.3-12.el10_2.5, libwinpr 3.10.3-5.el10_1.8, libwinpr 3.10.3-12.el10_2.5, freerdp-libs 3.10.3-5.el10_1.8, freerdp-libs 3.10.3-12.el10_2.5
    fixed: vendor fix RHSA-2026:16014
  • Red Hat Enterprise Linux AppStream AUS (v.8.4) freerdp 2.2.0-14.el8_4, libwinpr 2.2.0-14.el8_4, freerdp-libs 2.2.0-14.el8_4
    fixed: vendor fix RHSA-2026:19811
  • Red Hat Enterprise Linux AppStream AUS (v.8.6) freerdp 2.2.0-7.el8_6.8, libwinpr 2.2.0-7.el8_6.8, freerdp-libs 2.2.0-7.el8_6.8 Red Hat Enterprise Linux AppStream E4S (v.8.6) freerdp 2.2.0-7.el8_6.8, libwinpr 2.2.0-7.el8_6.8, freerdp-libs 2.2.0-7.el8_6.8
    fixed: vendor fix RHSA-2026:16814
show 14 more
  • Red Hat Enterprise Linux AppStream E4S (v.8.8) freerdp 2.2.0-12.el8_8.8, libwinpr 2.2.0-12.el8_8.8, freerdp-libs 2.2.0-12.el8_8.8
    fixed: vendor fix RHSA-2026:16777
  • Red Hat Enterprise Linux AppStream E4S (v.9.0) freerdp 2.4.1-3.el9_0.7, libwinpr 2.4.1-3.el9_0.7, freerdp-libs 2.4.1-3.el9_0.7
    fixed: vendor fix RHSA-2026:16485
  • Red Hat Enterprise Linux AppStream E4S (v.9.2) freerdp 2.4.1-6.el9_2.9, libwinpr 2.4.1-6.el9_2.9, freerdp-libs 2.4.1-6.el9_2.9
    fixed: vendor fix RHSA-2026:16483
  • Red Hat Enterprise Linux AppStream EUS (v. 10.0) freerdp 3.10.3-3.el10_0.7, libwinpr 3.10.3-3.el10_0.7, freerdp-libs 3.10.3-3.el10_0.7
    fixed: vendor fix RHSA-2026:20605
  • Red Hat Enterprise Linux AppStream EUS (v.9.4) freerdp 2.11.2-1.el9_4.8, libwinpr 2.11.2-1.el9_4.8, freerdp-libs 2.11.2-1.el9_4.8
    fixed: vendor fix RHSA-2026:16866
  • Red Hat Enterprise Linux AppStream EUS (v.9.6) freerdp 2.11.7-1.el9_6.10, libwinpr 2.11.7-1.el9_6.10, freerdp-libs 2.11.7-1.el9_6.10
    fixed: vendor fix RHSA-2026:16865
  • Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.4) freerdp 2.2.0-14.el8_4, libwinpr 2.2.0-14.el8_4, freerdp-libs 2.2.0-14.el8_4
    fixed: vendor fix RHSA-2026:19811
  • Red Hat Enterprise Linux AppStream TUS (v.8.6) freerdp 2.2.0-7.el8_6.8, libwinpr 2.2.0-7.el8_6.8, freerdp-libs 2.2.0-7.el8_6.8
    fixed: vendor fix RHSA-2026:16814
  • Red Hat Enterprise Linux AppStream TUS (v.8.8) freerdp 2.2.0-12.el8_8.8, libwinpr 2.2.0-12.el8_8.8, freerdp-libs 2.2.0-12.el8_8.8
    fixed: vendor fix RHSA-2026:16777
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) freerdp-devel 2.11.7-1.el9_7.7, freerdp-devel 2.11.7-7.el9_8.3, libwinpr-devel 2.11.7-1.el9_7.7, libwinpr-devel 2.11.7-7.el9_8.3, freerdp-debuginfo 2.11.7-1.el9_7.7, freerdp-debuginfo 2.11.7-7.el9_8.3, +6 more
    fixed: vendor fix RHSA-2026:16482
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) freerdp-server 3.10.3-5.el10_1.8, freerdp-server 3.10.3-12.el10_2.5
    fixed: vendor fix RHSA-2026:16014
  • Red Hat Enterprise Linux CodeReady Linux Builder EUS (v. 10.0) freerdp-server 3.10.3-3.el10_0.7
    fixed: vendor fix RHSA-2026:20605
  • Red Hat Enterprise Linux CRB (v. 8) freerdp-devel 2.11.7-9.el8_10, freerdp-debuginfo 2.11.7-9.el8_10, libwinpr-debuginfo 2.11.7-9.el8_10, freerdp-debugsource 2.11.7-9.el8_10, freerdp-libs-debuginfo 2.11.7-9.el8_10
    fixed: vendor fix RHSA-2026:16019
  • Red Hat Enterprise Linux Server (v. 7 ELS) freerdp 2.1.1-5.el7_9.9, libwinpr 2.1.1-5.el7_9.9, freerdp-libs 2.1.1-5.el7_9.9 Red Hat Enterprise Linux Server Optional (v. 7 ELS) freerdp-devel 2.1.1-5.el7_9.9, libwinpr-devel 2.1.1-5.el7_9.9, freerdp-debuginfo 2.1.1-5.el7_9.9
    fixed: vendor fix RHSA-2026:20546

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
Proof of concept is public
Automatable
yes
Technical impact
partial
Assessed
7 mo ago

Exploit prediction

0.36% chance of exploitation in the next 30 days, higher than 29% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-85x9-4xxp-xhm5 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
NVD 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

  • FreeRDP FreeRDP

Classification

Weakness
  • CWE-191 Integer Underflow (Wrap or Wraparound)
  • CWE-122 Heap-based Buffer Overflow

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.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.