{"schema_version":"1","data":[{"id":5524,"advisory_id":"b2454648-7d8d-4c3f-8751-745eedc1a499","revision":1,"source_id":"core-cve","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-76840","source_published_at":"2026-08-24T13:11:58.408+00:00","published_at":"2026-10-24T22:10:00.497635+00:00","extraction_method":"structured","technologies":["core-cve","rustdesk"],"cve_ids":["CVE-2026-76840"],"event_types":["advisory"],"payload":{"kind":"advisory","title":"RustDesk through 1.4.9 Heap Buffer Overflow via Unvalidated CLIPRDR FileContentsResponse Length","summary":"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.","evidence":"cve:CVE-2026-76840","products":[{"name":{"value":"rustdesk","evidence":"/containers/cna/affected/0/product"},"prerequisites":[],"fixed_versions":[],"affected_versions":[]}],"severity":"critical","structured":{"id":"CVE-2026-76840","aliases":["CVE-2026-76840"],"metrics":[{"format":"CVSS","cvssV4_0":{"version":"4.0","baseScore":8.5,"attackVector":"NETWORK","baseSeverity":"HIGH","vectorString":"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","userInteraction":"PASSIVE","attackComplexity":"LOW","attackRequirements":"NONE","privilegesRequired":"NONE","subIntegrityImpact":"HIGH","vulnIntegrityImpact":"NONE","subAvailabilityImpact":"HIGH","vulnAvailabilityImpact":"HIGH","subConfidentialityImpact":"LOW","vulnConfidentialityImpact":"NONE"}},{"format":"CVSS","cvssV3_1":{"scope":"CHANGED","version":"3.1","baseScore":9.6,"attackVector":"NETWORK","baseSeverity":"CRITICAL","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:H/A:H","integrityImpact":"HIGH","userInteraction":"REQUIRED","attackComplexity":"LOW","availabilityImpact":"HIGH","privilegesRequired":"NONE","confidentialityImpact":"LOW"}}],"affected":[{"vendor":"rustdesk","product":"rustdesk","versions":[{"status":"affected","version":"0","versionType":"semver","lessThanOrEqual":"1.4.9"}],"packageName":"rustdesk","collectionURL":"https://github.com/rustdesk/rustdesk","defaultStatus":"unaffected"}],"modified":"2026-10-01T15:21:11.754Z","provider":"cve","references":["https://github.com/rustdesk/rustdesk","https://github.com/rustdesk/rustdesk/blob/1.4.9/libs/clipboard/src/windows/wf_cliprdr.c","https://github.com/rustdesk/rustdesk/pull/15515","https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-m37j-jcr2-8gcc","https://www.vulncheck.com/advisories/rustdesk-through-heap-buffer-overflow-via-unvalidated-cliprdr-filecontentsresponse-length"],"provider_metadata":{"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2026-76840","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"version":"2.0.3","timestamp":"2026-08-24T16:26:40.462428Z"}}}],"providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2026-08-24T16:27:03.717Z"}}],"cna":{"orgId":"83251b91-4cc7-4094-a5c7-464a1b83ea10","shortName":"VulnCheck","dateUpdated":"2026-10-01T15:21:11.754Z"}}},"related_cves":[{"value":"CVE-2026-76840","evidence":"/cveMetadata/cveId"}],"security_relevant":true,"severity_evidence":"/containers/cna/metrics"}}],"next_after":5524,"next_before":5524}