What’s Vulnerable › Vulnerabilities

CVE-2026-109246: FreeRDP before 3.32.0 Shadow Server Divide-by-Zero via Frame Acknowledge PDU

• Severity: medium (CVSS 6.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-10-12 · updated 2026-10-18
• Weakness: CWE-191

Description

FreeRDP before 3.32.0 contains a divide-by-zero vulnerability in the freerdp-shadow-cli shadow server: the frame id in a client's Frame Acknowledge PDU is stored without a range check, so the in-flight frame count in shadow_encoder_inflight_frames() can underflow. An authenticated client can acknowledge a frame id one greater than the last frame sent, causing shadow_encoder_create_frame_id() to divide by zero (SIGFPE) and terminate the process, disconnecting all viewers.

Affected products

• FreeRDP: before 3.32.0 — fixed in 3.32.0

How to fix

Upgrade to a fixed version: FreeRDP 3.32.0. Check the vendor advisory for mitigations.

References

• https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-6vjv-4hm3-6698
• https://www.vulncheck.com/advisories/freerdp-before-3.32.0-shadow-server-divide-by-zero-via-frame-acknowledge-pdu
• https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-6vjv-4hm3-6698

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