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CVE-2026-40033

Freerdp remote code execution

8.8 HIGHPublic exploitEPSS 1.06%
  1. Published26 May 2026

Description

FreeRDP before 3.26.0 contains a heap-buffer-overflow vulnerability in gdi_CacheToSurface that allows remote attackers to write out-of-bounds heap memory. The vulnerability occurs because rectangle validation clamps coordinates to UINT16_MAX but performs copy operations using unclamped cache entry dimensions, enabling malicious RDP servers to trigger large out-of-bounds writes and potentially achieve remote code execution or client crash.

CVSS 3.1 breakdown

Attack vectorNetwork
Attack complexityLow
Privileges requiredNone
User interactionRequired
ScopeUnchanged
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Affected products

Freerdp< 3.26.0

Remediation

Fixed in
Freerdp≥ 3.26.0

References

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Frequently asked

Is CVE-2026-40033 being actively exploited?

CVE-2026-40033 is not in the CISA KEV catalog. A public exploit reference exists, so treat it as exploitable. Its EPSS exploit probability is 1.06%.

How severe is CVE-2026-40033?

CVE-2026-40033 has a CVSS 3.1 base score of 8.8, rated high. EPSS estimates a 1.06% probability of exploitation.

Which products are affected by CVE-2026-40033?

Affected products include Freerdp.

How do I fix CVE-2026-40033?

Upgrade affected software to a fixed version, for example Freerdp 3.26.0 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2026-40033 against the real software inventory on every managed device, as each hourly inventory arrives. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.