How severe is CVE-2026-40033?

CVE-2026-40033 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-40033 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (52nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-40033?

CVE-2026-40033 affects Freerdp. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-40033?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2026-40033 have an EU (EUVD) identifier?

Yes. CVE-2026-40033 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-31830.

When was CVE-2026-40033 published?

CVE-2026-40033 was published on 2026-05-26 and last updated on 2026-07-08.

CVE-2026-40033

CVE-2026-40033 is a high-severity vulnerability in Freerdp with a CVSS 3.x base score of 8.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-122.

Key facts

Severity: High (CVSS 3.x base score 8.8)
CVSS v4: 8.7
EPSS exploit prediction: 1% (52nd percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-31830
Weakness: CWE-122
Affected product: Freerdp
Published: 2026-05-26
Last modified: 2026-07-08

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.

Frequently asked questions

What is CVE-2026-40033?: 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.
How severe is CVE-2026-40033?: CVE-2026-40033 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-40033 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (52nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-40033?: CVE-2026-40033 affects Freerdp. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-40033?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-40033 have an EU (EUVD) identifier?: Yes. CVE-2026-40033 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-31830.
When was CVE-2026-40033 published?: CVE-2026-40033 was published on 2026-05-26 and last updated on 2026-07-08.

References

Affected products (1)

cpe:2.3:a:freerdp:freerdp:*:*:*:*:*:*:*:*

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