CVE-2026-76840

CRITICALPre-NVD 9.69.6—
EchelonGraph scoreHIGH confidence

Score 9.6 from GitHub Security Advisory (severity: HIGH) published 2026-08-24. the CNA's CVSS baseline 9.6; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: cna:vulncheck, epss, ghsa
Trending — 3 sources updated this week
9.6EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 9.6Exploit: None knownExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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.

CVSS v3
9.6
EG Score
9.6(high)
EG Risk
43(Track)
EG Risk 43/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity96% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
23%
KEV
Not listed

Published

August 24, 2026

Last Modified

August 29, 2026

Advisory Details (5)

Auto-updated Sep 14, 2026
Patch available. Sources: github_pr, github.
generic

RustDesk through 1.4.9 Heap Buffer Overflow via Unvalidated CLIPRDR FileContentsResponse Length | Advisories | VulnCheck

https://www.vulncheck.com/advisories/rustdesk-through-heap-buffer-overflow-via-unvalidated-cliprdr-filecontentsresponse-length
github Patch Available

Windows clipboard: `CliprdrStream_Read` copies a server-controlled length into the caller's buffer (heap overflow) · Advisory · FreeRDP/FreeRDP · GitHub

https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-m37j-jcr2-8gcc
github_pr

harden wf_cliprdr.c

Fix merged in rustdesk/rustdesk PR #15515 on 2026-07-07 — awaiting tagged release

https://github.com/rustdesk/rustdesk/pull/15515
generic

rustdesk/libs/clipboard/src/windows/wf_cliprdr.c at 1.4.9 · rustdesk/rustdesk · GitHub

https://github.com/rustdesk/rustdesk/blob/1.4.9/libs/clipboard/src/windows/wf_cliprdr.c
generic

GitHub - rustdesk/rustdesk: An open-source remote desktop application designed for self-hosting, as an alternative to TeamViewer. · GitHub

https://github.com/rustdesk/rustdesk

Vendor Advisories for CVE-2026-76840(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Weakness Classification(2)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 48× in last 7d / 196× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 196 total refreshes for this CVE.

  1. 2026-09-20 14:31 UTCGHSA enrichment
  2. 2026-09-20 10:06 UTCGHSA enrichment
  3. 2026-09-20 05:45 UTCGHSA enrichment
  4. 2026-09-20 01:24 UTCGHSA enrichment
  5. 2026-09-19 21:04 UTCGHSA enrichment
  6. 2026-09-19 16:42 UTCEG score recompute
  7. 2026-09-19 16:42 UTCGHSA enrichment
  8. 2026-09-19 12:21 UTCGHSA enrichment
  9. 2026-09-19 08:01 UTCGHSA enrichment
  10. 2026-09-19 03:40 UTCGHSA enrichment
  11. 2026-09-18 23:19 UTCEG score recompute
  12. 2026-09-18 23:19 UTCGHSA enrichment
  13. 2026-09-18 19:28 UTCEPSS rescore
  14. 2026-09-18 18:59 UTCGHSA enrichment
  15. 2026-09-18 14:38 UTCGHSA enrichment
  16. 2026-09-18 10:17 UTCGHSA enrichment
  17. 2026-09-18 05:56 UTCGHSA enrichment
  18. 2026-09-18 01:33 UTCGHSA enrichment
  19. 2026-09-17 21:12 UTCEG score recompute
  20. 2026-09-17 21:12 UTCGHSA enrichment
  21. 2026-09-17 13:08 UTCGHSA enrichment
  22. 2026-09-17 08:43 UTCGHSA enrichment
  23. 2026-09-17 04:23 UTCGHSA enrichment
  24. 2026-09-16 23:59 UTCGHSA enrichment
  25. 2026-09-16 19:38 UTCGHSA enrichment
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  1. 2026-09-16 15:07 UTCEG score recompute
  2. 2026-09-16 15:07 UTCGHSA enrichment
  3. 2026-09-16 14:08 UTCEPSS rescore
  4. 2026-09-16 10:45 UTCGHSA enrichment
  5. 2026-09-16 06:11 UTCEG score recompute
  6. 2026-09-16 06:11 UTCGHSA enrichment
  7. 2026-09-16 05:15 UTCEPSS rescore
  8. 2026-09-16 01:50 UTCGHSA enrichment
  9. 2026-09-15 21:29 UTCGHSA enrichment
  10. 2026-09-15 17:08 UTCGHSA enrichment
  11. 2026-09-15 12:48 UTCGHSA enrichment
  12. 2026-09-15 08:27 UTCGHSA enrichment
  13. 2026-09-15 04:06 UTCEG score recompute
  14. 2026-09-15 04:06 UTCGHSA enrichment
  15. 2026-09-15 03:12 UTCEPSS rescore
  16. 2026-09-14 23:44 UTCGHSA enrichment
  17. 2026-09-14 19:01 UTCGHSA enrichment
  18. 2026-09-14 14:27 UTCGHSA enrichment
  19. 2026-09-14 10:06 UTCGHSA enrichment
  20. 2026-09-14 05:23 UTCGHSA enrichment
  21. 2026-09-14 01:01 UTCGHSA enrichment
  22. 2026-09-13 20:40 UTCEG score recompute
  23. 2026-09-13 20:40 UTCGHSA enrichment
  24. 2026-09-13 16:19 UTCGHSA enrichment
  25. 2026-09-13 11:58 UTCGHSA enrichment
  26. 2026-09-13 07:38 UTCGHSA enrichment
  27. 2026-09-13 03:17 UTCGHSA enrichment
  28. 2026-09-12 22:56 UTCGHSA enrichment
  29. 2026-09-12 18:35 UTCEG score recompute
  30. 2026-09-12 18:35 UTCGHSA enrichment
  31. 2026-09-12 15:02 UTCEPSS rescore
  32. 2026-09-12 14:14 UTCGHSA enrichment
  33. 2026-09-12 09:53 UTCGHSA enrichment
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  35. 2026-09-12 01:11 UTCGHSA enrichment
  36. 2026-09-11 20:50 UTCGHSA enrichment
  37. 2026-09-11 16:24 UTCEG score recompute
  38. 2026-09-11 16:24 UTCGHSA enrichment
  39. 2026-09-11 14:53 UTCEPSS rescore
  40. 2026-09-11 12:03 UTCEG score recompute
  41. 2026-09-11 12:03 UTCGHSA enrichment
  42. 2026-09-11 07:06 UTCGHSA enrichment
  43. 2026-09-11 02:45 UTCGHSA enrichment
  44. 2026-09-10 22:24 UTCGHSA enrichment
  45. 2026-09-10 18:03 UTCGHSA enrichment
  46. 2026-09-10 13:42 UTCEG score recompute
  47. 2026-09-10 13:42 UTCGHSA enrichment
  48. 2026-09-10 09:35 UTCEPSS rescore
  49. 2026-09-10 09:16 UTCGHSA enrichment
  50. 2026-09-10 04:55 UTCGHSA enrichment
  51. 2026-09-10 00:34 UTCGHSA enrichment
  52. 2026-09-09 18:56 UTCGHSA enrichment
  53. 2026-09-09 14:34 UTCGHSA enrichment
  54. 2026-09-09 10:13 UTCGHSA enrichment
  55. 2026-09-09 05:52 UTCGHSA enrichment
  56. 2026-09-09 01:32 UTCEG score recompute
  57. 2026-09-09 01:32 UTCGHSA enrichment
  58. 2026-09-08 22:01 UTCEPSS rescore
  59. 2026-09-08 04:52 UTCGHSA enrichment
  60. 2026-09-08 00:31 UTCGHSA enrichment
  61. 2026-09-07 20:11 UTCEG score recompute
  62. 2026-09-07 20:11 UTCGHSA enrichment
  63. 2026-09-07 15:51 UTCGHSA enrichment
  64. 2026-09-07 11:30 UTCGHSA enrichment
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  66. 2026-09-07 02:42 UTCGHSA enrichment
  67. 2026-09-06 22:20 UTCGHSA enrichment
  68. 2026-09-06 17:58 UTCEG score recompute
  69. 2026-09-06 17:58 UTCGHSA enrichment
  70. 2026-09-06 13:48 UTCEPSS rescore
  71. 2026-09-06 13:37 UTCGHSA enrichment
  72. 2026-09-06 09:16 UTCGHSA enrichment
  73. 2026-09-06 04:43 UTCGHSA enrichment
  74. 2026-09-06 00:22 UTCGHSA enrichment
  75. 2026-09-05 19:57 UTCGHSA enrichment

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-76840?
CVE-2026-76840 is a critical vulnerability published on August 24, 2026. 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, CliprdrStreamRead in libs/clipboard/src/windows/wfcliprdr.c requests…
When was CVE-2026-76840 disclosed?
CVE-2026-76840 was first published in the National Vulnerability Database on August 24, 2026, with the most recent update on August 29, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-76840 actively exploited?
CVE-2026-76840 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 77.2% of all scored CVEs.
What is the CVSS score of CVE-2026-76840?
CVE-2026-76840 has a CVSS v4.0 base score of 9.6 (CNA self-assessment; NVD's own analysis pending).
How do I remediate CVE-2026-76840?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-76840, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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