Vulnerability · Published Mar 13, 2026 · Assigned by GitHub_M
CVE-2026-31883FreeRDP has a `size_t` underflow in ADPCM decoder leads to heap-buffer-overflow write
Medium 6.5
In plain English
A medium-severity heap buffer overflow in FreeRDP from FreeRDP. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 27% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux:10 | freerdp | 2:3.10.3-5.el10_1.8 | ALSA-2026:16014 |
| AlmaLinux:8 | freerdp | 2:2.11.7-9.el8_10 | ALSA-2026:16019 |
| AlmaLinux:9 | freerdp | 2:2.11.7-1.el9_7.7 | ALSA-2026:16482 |
| AlmaLinux:9 | freerdp | 2:2.11.7-7.el9_8.3 | ALSA-2026:19358 |
| AlmaLinux:10 | freerdp-devel | 2:3.10.3-5.el10_1.8 | ALSA-2026:16014 |
| AlmaLinux:8 | freerdp-devel | 2:2.11.7-9.el8_10 | ALSA-2026:16019 |
| AlmaLinux:9 | freerdp-devel | 2:2.11.7-7.el9_8.3 | ALSA-2026:19358 |
| AlmaLinux:9 | freerdp-devel | 2:2.11.7-1.el9_7.7 | ALSA-2026:16482 |
| AlmaLinux:10 | freerdp-libs | 2:3.10.3-5.el10_1.8 | ALSA-2026:16014 |
| AlmaLinux:8 | freerdp-libs | 2:2.11.7-9.el8_10 | ALSA-2026:16019 |
| AlmaLinux:9 | freerdp-libs | 2:2.11.7-7.el9_8.3 | ALSA-2026:19358 |
| AlmaLinux:9 | freerdp-libs | 2:2.11.7-1.el9_7.7 | ALSA-2026:16482 |
| AlmaLinux:10 | freerdp-server | 2:3.10.3-5.el10_1.8 | ALSA-2026:16014 |
| AlmaLinux:10 | libwinpr | 2:3.10.3-5.el10_1.8 | ALSA-2026:16014 |
| AlmaLinux:8 | libwinpr | 2:2.11.7-9.el8_10 | ALSA-2026:16019 |
| AlmaLinux:9 | libwinpr | 2:2.11.7-1.el9_7.7 | ALSA-2026:16482 |
| AlmaLinux:9 | libwinpr | 2:2.11.7-7.el9_8.3 | ALSA-2026:19358 |
| AlmaLinux:10 | libwinpr-devel | 2:3.10.3-5.el10_1.8 | ALSA-2026:16014 |
| AlmaLinux:8 | libwinpr-devel | 2:2.11.7-9.el8_10 | ALSA-2026:16019 |
| AlmaLinux:9 | libwinpr-devel | 2:2.11.7-7.el9_8.3 | ALSA-2026:19358 |
| AlmaLinux:9 | libwinpr-devel | 2:2.11.7-1.el9_7.7 | ALSA-2026:16482 |
| Alpine:v3.23 | freerdp | 3.24.0-r0 | ALPINE-CVE-2026-31883 |
| Alpine:v3.24 | freerdp | 3.24.0-r0 | ALPINE-CVE-2026-31883 |
| Debian:12 | freerdp2 | no fix listed | DEBIAN-CVE-2026-31883 |
| Debian:13 | freerdp3 | 3.15.0+dfsg-2.1+deb13u2 | DEBIAN-CVE-2026-31883 |
| Debian:14 | freerdp3 | 3.24.0+dfsg-1 | DEBIAN-CVE-2026-31883 |
| Rocky Linux:10 | freerdp | 2:3.10.3-12.el10_2.5 | RLSA-2026:19142 |
| Rocky Linux:10 | freerdp | 2:3.10.3-5.el10_1.8 | RLSA-2026:16014 |
| Rocky Linux:8 | freerdp | 2:2.11.7-9.el8_10 | RLSA-2026:16019 |
| Rocky Linux:9 | freerdp | 2:2.11.7-7.el9_8.3 | RLSA-2026:19358 |
| Rocky Linux:9 | freerdp | 2:2.11.7-1.el9_7.7 | RLSA-2026:16482 |
| Ubuntu:22.04:LTS | freerdp2 | no fix listed | UBUNTU-CVE-2026-31883 |
| Ubuntu:24.04:LTS | freerdp3 | 3.30.0+dfsg-0ubuntu0.24.04.1 | USN-8561-1 |
| Ubuntu:24.04:LTS | freerdp3 | 3.30.0+dfsg-0ubuntu0.24.04.1 | UBUNTU-CVE-2026-31883 |
| Ubuntu:25.10 | freerdp3 | no fix listed | UBUNTU-CVE-2026-31883 |
| Ubuntu:26.04:LTS | freerdp3 | 3.30.0+dfsg-0ubuntu0.26.04.1 | USN-8561-1 |
Affected products (as reported)
Weakness: CWE-191, CWE-122 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N