CVE-2026-109251 FreeRDP CVE debrief

Who should care

Defenders responsible for systems using FreeRDP for RDP connections, particularly those allowing video connections, should assess exposure and prioritize updates to prevent potential out-of-bounds writes.

Why it matters

Defenders should prioritize updating FreeRDP to version 3.32.0 or later to prevent potential out-of-bounds writes. Systems using FreeRDP for RDP connections should be assessed for exposure, particularly those allowing video connections. The vulnerability allows a malicious RDP server to send a negative topLevelLeft to clients connecting with /video, resulting in an out-of-bounds write of decoded H.264 picture data or a client abort. Evidence is limited, and verification of affected versions and potential exploitation is required.

• Potential out-of-bounds write of decoded H.264 picture data
• Potential client abort due to malicious RDP server activity
• Requires verification of affected versions and potential exploitation
• Prioritization of updates to FreeRDP version 3.32.0 or later

Technical summary

The vulnerability occurs in FreeRDP before version 3.32.0, where the server-supplied signed MS-RDPEGT geometry origin is stored unchecked in an unsigned video surface coordinate. This causes the blit clamp in gdiVideoShowSurface() to wrap in 32-bit arithmetic and be skipped, allowing a malicious RDP server to send a negative topLevelLeft to clients connecting with /video, resulting in an out-of-bounds write of decoded H.264 picture data or a client abort.

Defensive priority

Defenders should prioritize updating FreeRDP to version 3.32.0 or later to prevent potential out-of-bounds writes. Systems using FreeRDP for RDP connections should be assessed for exposure, particularly those allowing video connections.

Recommended defensive actions

• Update FreeRDP to version 3.32.0 or later
• Assess systems using FreeRDP for RDP connections, particularly those allowing video connections, for exposure
• Monitor for potential malicious RDP server activity
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Check relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

The CVE record and source item provide details on the vulnerability, including its description and affected versions. However, there is limited information on potential exploitation or victim impact. Evidence from the CVE Program and NVD detail page indicates that FreeRDP before version 3.32.0 is vulnerable. Defenders should verify affected versions and assess exposure, particularly for systems allowing video connections. Limited evidence suggests potential out-of-bounds writes and client aborts. Further verification is required to确定受

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.