---
cve: "CVE-2026-40033"
severity: "HIGH"
cvss: 8.6
epss: "1%"
vendor: "FreeRDP"
kev: false
exploited: false
published: "2026-05-26 15:16:34"
tags: [cve, security, high]
source: tsecurity.de CVE-Dossier
exported: "2026-09-07T07:48:31+02:00"
---

# CVE-2026-40033

> 8.6 HIGH · 🧪 PoC

## Beschreibung

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-Vektor

```
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
```

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Netzwerk | bad |
| AC Komplexität | Gering | bad |
| PR Privilegien | Keine | bad |

## Patch verfügbar (OSV)

- 3f6d7cb1f8973cc84c66b258a9a61c4e2b2f30a6 (Commit)
- d7508ebcd82842a691ae4941e5104d14240a89ae (Commit)

## Referenzen

- <https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-p6r2-4hgm-m6ff>
- <https://github.com/FreeRDP/FreeRDP/pull/12713>
- <https://github.com/FreeRDP/FreeRDP/commit/d7508ebcd82842a691ae4941e5104d14240a89ae>
- <https://www.vulncheck.com/advisories/freerdp-heap-buffer-overflow-in-gdi-cachetosurface-via-rectangle-validation-bypass>
- <https://access.redhat.com/errata/RHSA-2026:36203>
- <https://access.redhat.com/errata/RHSA-2026:46393>
- <https://access.redhat.com/security/cve/CVE-2026-40033>
- <https://bugzilla.redhat.com/show_bug.cgi?id=2481473>
- <https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-40033.json>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-40033) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_