CVE-2026-109939

6.5Medium

Published 13 Oct 2026 · NVD status: Undergoing Analysis · AI triage by gemini-3.8-flash

6.5Medium

Attack vector: Network
Complexity: Low
Privileges needed: None
User interaction: Required
Impact: High impact on availability
Weakness: CWE-476

Impact

A malicious RDP server can crash connecting FreeRDP clients, causing a denial of service. The attacker needs a user to initiate an RDP connection with non-default Bitmap Cache V3 options enabled.

Root cause

A NULL pointer dereference occurs in update_read_cache_bitmap_v3_order() because it accesses uninitialized client bitmap cache memory when the CBR3_DO_NOT_CACHE flag is set.

Affected systems

FreeRDP 3.27.1 before 3.32.0

CVSS v3.1 · CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

Fix & remediation

Upgrade FreeRDP to version 3.32.0 or higher. If patching must wait, avoid using the non-default Bitmap Cache V3 flags (/cache:codec:rfx, /cache:codec:nsc, or /cache:codec:jpeg) when launching connections.

shell

$ sudo apt-get update && sudo apt-get install --only-upgrade freerdp3-x11

AI-suggested. Run it in staging first and check it against the vendor advisory. Why?

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NVD description

FreeRDP 3.27.1 before 3.32.0 contains a NULL pointer dereference in update_read_cache_bitmap_v3_order() in libfreerdp/core/orders.c, which accesses the client bitmap cache when the CBR3_DO_NOT_CACHE flag is set, even though the cache is not yet initialized before Demand Active. A malicious or compromised RDP server can send a Cache Bitmap V3 order during connection setup to crash a connecting client that has enabled the non-default Bitmap Cache V3 feature (/cache:codec:<rfx|nsc|jpeg>).

References

Source: nvd.nist.gov/vuln/detail/CVE-2026-109939