Vulnerability · Published Sep 15, 2026 · Assigned by VulnCheck
CVE-2026-91953FreeRDP before 3.31.0 Heap Buffer Overflow via LB_LOAD_BALANCE_INFO
Medium 6.5
In plain English
A medium-severity 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 0.5% (higher than 41% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
FreeRDP versions before 3.31.0 contain a heap buffer overflow vulnerability in nego_send_negotiation_request() that fails to validate the LB_LOAD_BALANCE_INFO field length before writing to a fixed 512-byte buffer. A malicious RDP server or man-in-the-middle can send a Server Redirection PDU with an oversized LB_LOAD_BALANCE_INFO value to overflow the buffer with attacker-controlled content, causing denial of service or heap corruption before authentication completes.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux:10 | freerdp | 2:3.10.3-12.el10_2.14 | ALSA-2026:75570 |
| AlmaLinux:8 | freerdp | 2:2.11.7-14.el8_10 | ALSA-2026:76747 |
| AlmaLinux:9 | freerdp | 2:2.11.7-7.el9_8.8 | ALSA-2026:76755 |
| AlmaLinux:10 | freerdp-devel | 2:3.10.3-12.el10_2.14 | ALSA-2026:75570 |
| AlmaLinux:8 | freerdp-devel | 2:2.11.7-14.el8_10 | ALSA-2026:76747 |
| AlmaLinux:9 | freerdp-devel | 2:2.11.7-7.el9_8.8 | ALSA-2026:76755 |
| AlmaLinux:10 | freerdp-libs | 2:3.10.3-12.el10_2.14 | ALSA-2026:75570 |
| AlmaLinux:8 | freerdp-libs | 2:2.11.7-14.el8_10 | ALSA-2026:76747 |
| AlmaLinux:9 | freerdp-libs | 2:2.11.7-7.el9_8.8 | ALSA-2026:76755 |
| AlmaLinux:10 | freerdp-server | 2:3.10.3-12.el10_2.14 | ALSA-2026:75570 |
| AlmaLinux:10 | libwinpr | 2:3.10.3-12.el10_2.14 | ALSA-2026:75570 |
| AlmaLinux:8 | libwinpr | 2:2.11.7-14.el8_10 | ALSA-2026:76747 |
| AlmaLinux:9 | libwinpr | 2:2.11.7-7.el9_8.8 | ALSA-2026:76755 |
| AlmaLinux:10 | libwinpr-devel | 2:3.10.3-12.el10_2.14 | ALSA-2026:75570 |
| AlmaLinux:8 | libwinpr-devel | 2:2.11.7-14.el8_10 | ALSA-2026:76747 |
| AlmaLinux:9 | libwinpr-devel | 2:2.11.7-7.el9_8.8 | ALSA-2026:76755 |
| Debian:12 | freerdp2 | no fix listed | DEBIAN-CVE-2026-91953 |
| Debian:13 | freerdp3 | no fix listed | DEBIAN-CVE-2026-91953 |
| Debian:14 | freerdp3 | 3.31.0+dfsg-1 | DEBIAN-CVE-2026-91953 |
| Rocky Linux:10 | freerdp | 2:3.10.3-12.el10_2.14 | RLSA-2026:75570 |
| Rocky Linux:8 | freerdp | 2:2.11.7-14.el8_10 | RLSA-2026:76747 |
| Rocky Linux:9 | freerdp | 2:2.11.7-7.el9_8.8 | RLSA-2026:76755 |
| Ubuntu:22.04:LTS | freerdp2 | no fix listed | UBUNTU-CVE-2026-91953 |
| Ubuntu:24.04:LTS | freerdp3 | 3.31.0+dfsg-0ubuntu0.24.04.1 | UBUNTU-CVE-2026-91953 |
| Ubuntu:26.04:LTS | freerdp3 | 3.31.0+dfsg-0ubuntu0.26.04.1 | UBUNTU-CVE-2026-91953 |
Affected products (as reported)
Weakness: CWE-120 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
References
- GitHub Security Advisory (GHSA-r9pv-ffph-6gg6) vendor-advisory
- VulnCheck Advisory: FreeRDP before 3.31.0 Heap Buffer Overflow via LB_LOAD_BALANCE_INFO third-party-advisory