> CVE-2026-76840 [HIGH]

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PUBLISHED
2026-08-24 14:17
MODIFIED
2026-08-24 14:17
CVSS_SCORE V3
8.5
EPSS (Prob. Exploit)
0.43%
Top 63.4%
DATA SOURCES:
NVD đź”— 2026-08-24 CWE MITRE đź”— 2026-09-01 FIRST EPSS đź”— 2026-10-25 OSV đź”— 2026-08-31

> DESCRIPTION

RustDesk's Windows clipboard redirection copies a peer-supplied length into a fixed-size caller buffer without an upper bound check. When an OLE paste consumer such as explorer.exe calls IStream::Read with a buffer of cb bytes, CliprdrStream_Read in libs/clipboard/src/windows/wf_cliprdr.c requests that many bytes of a remote file through cliprdr_send_request_filecontents and then executes CopyMemory(pv, clipboard->req_fdata, clipboard->req_fsize), where req_fsize is taken verbatim from the peer's CLIPRDR FileContentsResponse by wf_cliprdr_server_file_contents_response (req_fsize = fileContentsResponse->cbRequested) and is never clamped to cb anywhere in the chain. The function's only length comparison, req_fsize < cb, handles the short-read case and is evaluated after the copy has already occurred. A malicious or compromised peer that answers a small file-contents read with an oversized response therefore writes attacker-chosen data past the end of the paste consumer's heap buffer when the local user pastes clipboard file contents offered by the remote side. The file is a fork of FreeRDP's client/Windows/wf_cliprdr.c, where the same defect is CVE-2026-68579, fixed in FreeRDP 3.30.0.

> AFFECTED_PRODUCTS

ℹ️ Aucun produit affecté n'a encore été publié par NVD pour cette CVE.

> CVSS V3 METRICS

CVSS_VECTOR
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:L/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

> MÉTRIQUES CVSS DÉTAILLÉES

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:L/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Métrique Valeur Interprétation
AV (Vecteur d'Attaque)
Attack Vector
Network (N)
Exploit possible à distance via réseau (HTTP, API, etc.)
AC (Complexité d'Attaque)
Attack Complexity
Low (L)
Peu de conditions requises pour exploiter
PR (Privilèges Requis)
Privileges Required
None (N)
Aucune authentification requise
UI (Interaction Utilisateur)
User Interaction
Unknown (P)
Interaction inconnue
S (Périmètre)
Scope
Unchanged (U)
Impact reste dans le périmètre du composant compromis
C (Impact Confidentialité)
Confidentiality Impact
None (N)
Aucune divulgation d'informations
I (Impact Intégrité)
Integrity Impact
None (N)
Aucune modification de données possible
A (Impact Disponibilité)
Availability Impact
High (H)
Interruption totale du service possible

> RÉSUMÉ DES IMPACTS

Confidentialité
None
Aucune divulgation d'informations
Intégrité
None
Aucune modification de données possible
Disponibilité
High
Interruption totale du service possible

> WEAKNESSES

CWE-20 CWE-787

> CWE DETAILED DESCRIPTIONS

CWE-20: Improper Input Validation - The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly. | CWE-787: Out-of-bounds Write - The product writes data past the end, or before the beginning, of the intended buffer.

> OSV (GOOGLE OPEN SOURCE VULNERABILITIES)

RustDesk through 1.4.9 Heap Buffer Overflow via Unvalidated CLIPRDR FileContentsResponse Length

AFFECTED PACKAGES:
Unknown / Unknown
35 versions affected
ALIASES:
CVE-2026-68579, GHSA-m37j-jcr2-8gcc

> HISTORIQUE DES MODIFICATIONS

Première apparition
24/08/2026 14:17
Source: NVD
📊 ENRICHISSEMENT 01/09/2026 06:02
CWE
Champ modifié: Description CWE
Ancienne valeur:
N/A
Nouvelle valeur:
CWE-20: Improper Input Validation - The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process...
Total des modifications: 1 Dernière mise à jour: 1 month ago

> REFERENCES

https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-m37j-jcr2-8gcc
https://github.com/rustdesk/rustdesk
https://github.com/rustdesk/rustdesk/blob/1.4.9/libs/clipboard/src/windows/wf_cl...
https://github.com/rustdesk/rustdesk/pull/15515
https://www.vulncheck.com/advisories/rustdesk-through-heap-buffer-overflow-via-u...
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