CVE-2026-109256 FreeRDP CVE debrief

Who should care

Defenders responsible for FreeRDP deployments should assess exposure and prioritize verification and updates. Defenders should also review relevant monitoring, detection, and logs for exposed assets that need extra review. Security teams should track exceptions, retest remediated assets, and close the item only after evidence is documented.

Why it matters

Defenders should prioritize verifying and updating FreeRDP to a version outside the affected range, assessing exposure, and implementing compensating controls to prevent potential client crashes and denial of service.

• Client crashes due to out-of-bounds memcpy
• Potential for malicious RDP clipboard peers to cause denial of service

Technical summary

The vulnerability exists in the WinPR png_write_data callback, where a malicious RDP clipboard peer can supply a large CF_DIB image that triggers out-of-bounds memcpy during PNG conversion, causing a client crash. The vulnerability could lead to client crashes and potential denial of service. Defenders should prioritize verifying and updating FreeRDP to a version outside the affected range, assessing exposure, and implementing compensating controls to prevent potential client crashes and denial of service. The CVE description and CVSS score indicate a medium severity vulnerability.

Defensive priority

Defenders should prioritize verifying and updating FreeRDP to a version outside the affected range, assessing exposure, and implementing compensating controls.

Recommended defensive actions

• Verify and update FreeRDP to a version outside the affected range
• Assess exposure and implement compensating controls
• Monitor for suspicious RDP activity
• Review 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
• Plan vendor-supported updates or mitigations through normal change control where exposure is confirmed

Evidence notes

The CVE Program record and NVD vulnerability detail provide official information on the vulnerability. The CVE description and CVSS score indicate a medium severity vulnerability. Evidence is limited; defenders should verify and update FreeRDP to a version outside the affected range, assessing exposure, and implementing compensating controls to prevent potential client crashes and denial of service. The vulnerability exists in the WinPR png_write_data callback, where a malicious RDP clipboard peer can supply a large CF_DIB image that

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.