---
id: CVE-2026-63633
title: FreeRDP is a free implementation of the Remote Desktop Protocol
summary: >-
  FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to
  3.28.0, freerdp_dsp_decode_opus in libfreerdp/codec/dsp.c calls
  Stream_EnsureRemainingCapacity on context->common.buffer even though
  opus_decode writes decoded PCM…
severity: high
cwe:
  - CWE-122
  - CWE-120
published: '2026-08-19'
updated: '2026-09-09'
sourceUpdated: '2026-09-09T21:19:49.197'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-63633'
references:
  - url: >-
      https://github.com/FreeRDP/FreeRDP/commit/0ed1f95d36913581cf31124f94eb5843d4263eae
    label: security-advisories@github.com
  - url: 'https://github.com/FreeRDP/FreeRDP/pull/12993'
    label: security-advisories@github.com
  - url: 'https://github.com/FreeRDP/FreeRDP/releases/tag/3.28.0'
    label: security-advisories@github.com
  - url: 'https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-72j9-356v-88xq'
    label: security-advisories@github.com
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-63633.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-63633'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2519826'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-63633'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-63633'
  - url: 'https://access.redhat.com/errata/RHSA-2026:61378'
  - url: 'https://access.redhat.com/errata/RHSA-2026:68706'
tags:
  - nvd
  - csaf
  - vex
  - red-hat
epss: 0.00459
epssPercentile: 0.38956
ingestedAt: '2026-09-09T21:22:45.541Z'
vendor: Red Hat
product: Red Hat Enterprise Linux AppStream (v. 10)
affected:
  - enterprise_linux 9
  - enterprise_linux_appstream_v_10
  - enterprise_linux_codeready_linux_builder_v_10
patched:
  - enterprise_linux_appstream_v_10
  - enterprise_linux_codeready_linux_builder_v_10
cvss: 8.8
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H'
cvssSource: vendor
---

## Overview

FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.28.0, freerdp_dsp_decode_opus in libfreerdp/codec/dsp.c calls Stream_EnsureRemainingCapacity on context->common.buffer even though opus_decode writes decoded PCM into the caller-supplied out stream. A malicious RDP server that negotiates WAVE_FORMAT_OPUS with a client built with WITH_OPUS enabled and WITH_DSP_FFMPEG disabled can make libopus write a large decoded frame beyond the 4096-byte StreamPool_Take destination used by channels/rdpsnd/client/rdpsnd_main.c. This can corrupt the client heap, crash the client, and may permit code execution. This issue is fixed in version 3.28.0.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Vendor advisories

- **RHSA-2026:61378** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 10), Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) · released 2026-08-31 · [advisory](https://access.redhat.com/errata/RHSA-2026:61378)
- **Red Hat VEX** · Important · affected: Red Hat Enterprise Linux 9 · no fix planned: Red Hat Enterprise Linux 9 · updated 2026-09-17 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-63633.json)
- **RHSA-2026:68706** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream EUS (v. 10.0), Red Hat Enterprise Linux CodeReady Linux Builder EUS (v. 10.0) · released 2026-09-17 · [advisory](https://access.redhat.com/errata/RHSA-2026:68706)