CVE-2026-111881 FreeRDP CVE debrief

Who should care

Defenders responsible for FreeRDP deployments, particularly those using versions 3.14.1 to 3.32.0, should assess exposure and prioritize patching. This includes reviewing compensating controls for exposed systems, verifying and applying patches, and monitoring for suspicious RDP clipboard activity. Security teams should also track exceptions, retest remediated assets, and close the item only after evidence is documented.

Why it matters

CVE-2026-111881 is a high-severity vulnerability in FreeRDP that allows a malicious RDP peer to crash the client or execute arbitrary code. Defenders should prioritize patching and monitoring for suspicious activity.

• Potential client crashes or out-of-bounds writes via crafted RDP clipboard content
• Requires verification of FreeRDP version and exposure to untrusted RDP peers
• Patching priority for versions 3.14.1 to 3.32.0

Technical summary

FreeRDP from 3.14.1 before 3.32.0 contains an integer underflow in the WinPR BMP writer. A malicious RDP clipboard peer can return a crafted 1-bpp BMP processed by clipboard_synthesize_image_format_to_bmp for CF_DIB/CF_DIBV5, crashing the client or causing an out-of-bounds write. The vulnerability arises from a mismatched stride calculation that passes SIZE_MAX - 3 to Stream_Zero for sub-byte images. Defenders should prioritize verifying and applying patches for FreeRDP versions 3.14.1 to 3.32.0, and monitor for suspicious RDP clipboard activity.

Defensive priority

Defenders should prioritize verifying and applying patches for FreeRDP versions 3.14.1 to 3.32.0, and monitor for suspicious RDP clipboard activity.

Recommended defensive actions

• Verify and apply patches for FreeRDP versions 3.14.1 to 3.32.0
• Monitor for suspicious RDP clipboard activity
• Restrict RDP access to trusted peers
• 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 NVD entry provide details on the integer underflow vulnerability in FreeRDP's WinPR BMP writer. The vulnerability allows a malicious RDP clipboard peer to return a crafted 1-bpp BMP processed by clipboard_synthesize_image_format_to_bmp for CF_DIB/CF_DIBV5, crashing the client or causing an out-of-bounds write. Evidence is limited to public CVE and NVD records; further verification is needed to confirm affected deployments and validate vendor guidance.

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.