CVE-2026-76840

CRITICALPre-NVD 9.69.6
EchelonGraph scoreMEDIUM confidence

“—” beside the score: it is equal to the CVSS score beside it.

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: the CNA's CVSS, EPSS, GitHub Security Advisory
Trending — 3 sources updated this week
9.6EG
EchelonGraph verdictPlan mitigationRemediate within your standard update timelines (the SSVC decision on this page).
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.4%CVSS: 9.6Exploit: None knownExposed services: Not assessed

A fix is referenced (a reference tagged "Patch", often a source commit), but no release containing it is confirmed — find the release that contains it; until it is applied, mitigate (WAF / firewall / segmentation).

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
9.6CRITICALmedium confidence
EG Risk
43
EG Risk 43/100

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 (value × EchelonGraph’s weight)
Severity96% × 45%
The EG Score, 9.6 of 10.
Exploitation0.4% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at every mission impact level.
Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: A fix is referenced, but no release containing it is confirmed. Check the referenced fix and the vendor's advisory for a release that contains it and apply that within your standard update timelines; until then, restrict network exposure of the affected system or apply the vendor's mitigation.
EPSS PROB
0.4%
EPSS %ILE
35th
KEV
Not listed

SSVC (CISA's decision table, applied by EchelonGraph)Track at every mission impact level.

A fix is referenced, but no release containing it is confirmed. Check the referenced fix and the vendor's advisory for a release that contains it and apply that within your standard update timelines; until then, restrict network exposure of the affected system or apply the vendor's mitigation.

Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

August 24, 2026

Last Modified

October 1, 2026

Advisory Details (5)

Auto-updated Oct 2, 2026
Fix referenced — no release confirmed yet. Sources: github_pr, github.
Web page

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 advisoryMentions a patch (unverified)

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 pull request

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
Web page

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
Web page

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 22× in last 7d / 174× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. 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. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.

Showing the most recent 100 of 326 refreshes on record for this CVE.

A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. None are among the latest 100 rows. The 226 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-13 16:35 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  2. 2026-10-13 05:44 UTCEG score recompute
  3. 2026-10-13 05:44 UTCGHSA enrichmentGHSA-8m44-j2jr-wmrp · GitHub severity HIGH · GitHub CVSS 9.6
  4. 2026-10-12 16:35 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  5. 2026-10-12 15:38 UTCEG score recompute
  6. 2026-10-12 05:30 UTCGHSA enrichmentGHSA-8m44-j2jr-wmrp · GitHub severity HIGH · GitHub CVSS 9.6
  7. 2026-10-11 19:23 UTCEG score recompute
  8. 2026-10-11 16:39 UTCEG score recompute
  9. 2026-10-11 13:58 UTCEG score recompute
  10. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  11. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  12. 2026-10-10 13:06 UTCEG score recompute
  13. 2026-10-10 13:05 UTCGHSA enrichmentGHSA-8m44-j2jr-wmrp · GitHub severity HIGH · GitHub CVSS 9.6
  14. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  15. 2026-10-09 04:58 UTCEG score recompute
  16. 2026-10-09 04:58 UTCGHSA enrichmentGHSA-8m44-j2jr-wmrp · GitHub severity HIGH · GitHub CVSS 9.6
  17. 2026-10-08 17:13 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  18. 2026-10-08 08:23 UTCGHSA enrichmentGHSA-8m44-j2jr-wmrp · GitHub severity HIGH · GitHub CVSS 9.6
  19. 2026-10-08 04:03 UTCEG score recompute
  20. 2026-10-08 04:02 UTCGHSA enrichmentGHSA-8m44-j2jr-wmrp · GitHub severity HIGH · GitHub CVSS 9.6
  21. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  22. 2026-10-07 10:25 UTCGHSA enrichmentGHSA-8m44-j2jr-wmrp · GitHub severity HIGH · GitHub CVSS 9.6
  23. 2026-10-07 05:58 UTCGHSA enrichmentGHSA-8m44-j2jr-wmrp · GitHub severity HIGH · GitHub CVSS 9.6
  24. 2026-10-07 01:37 UTCGHSA enrichmentGHSA-8m44-j2jr-wmrp · GitHub severity HIGH · GitHub CVSS 9.6
  25. 2026-10-06 21:15 UTCGHSA enrichmentGHSA-8m44-j2jr-wmrp · GitHub severity HIGH · GitHub CVSS 9.6
Show 75 more
  1. 2026-10-06 16:41 UTCEG score recompute
  2. 2026-10-06 16:41 UTCGHSA enrichmentGHSA-8m44-j2jr-wmrp · GitHub severity HIGH · GitHub CVSS 9.6
  3. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  4. 2026-10-06 12:06 UTCGHSA enrichmentGHSA-8m44-j2jr-wmrp · GitHub severity HIGH · GitHub CVSS 9.6
  5. 2026-10-06 07:45 UTCGHSA enrichmentGHSA-8m44-j2jr-wmrp · GitHub severity HIGH · GitHub CVSS 9.6
  6. 2026-10-06 02:53 UTCGHSA enrichmentGHSA-8m44-j2jr-wmrp · GitHub severity HIGH · GitHub CVSS 9.6
  7. 2026-10-05 18:56 UTCEG score recompute
  8. 2026-10-05 18:56 UTCGHSA enrichmentGHSA-8m44-j2jr-wmrp · GitHub severity HIGH · GitHub CVSS 9.6
  9. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  10. 2026-10-05 14:32 UTCGHSA enrichmentGHSA-8m44-j2jr-wmrp · GitHub severity HIGH · GitHub CVSS 9.6
  11. 2026-10-05 10:10 UTCGHSA enrichmentGHSA-8m44-j2jr-wmrp · GitHub severity HIGH · GitHub CVSS 9.6
  12. 2026-10-05 05:49 UTCGHSA enrichmentGHSA-8m44-j2jr-wmrp · GitHub severity HIGH · GitHub CVSS 9.6
  13. 2026-10-05 01:28 UTCEG score recompute
  14. 2026-10-05 01:28 UTCGHSA enrichmentGHSA-8m44-j2jr-wmrp · GitHub severity HIGH · GitHub CVSS 9.6
  15. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  16. 2026-10-04 20:43 UTCGHSA enrichmentGHSA-8m44-j2jr-wmrp · GitHub severity HIGH · GitHub CVSS 9.6
  17. 2026-10-04 15:36 UTCGHSA enrichmentGHSA-8m44-j2jr-wmrp · GitHub severity HIGH · GitHub CVSS 9.6
  18. 2026-10-04 11:08 UTCGHSA enrichmentGHSA-8m44-j2jr-wmrp · GitHub severity HIGH · GitHub CVSS 9.6
  19. 2026-10-04 06:41 UTCGHSA enrichmentGHSA-8m44-j2jr-wmrp · GitHub severity HIGH · GitHub CVSS 9.6
  20. 2026-10-04 02:20 UTCGHSA enrichmentGHSA-8m44-j2jr-wmrp · GitHub severity HIGH · GitHub CVSS 9.6
  21. 2026-10-03 20:53 UTCGHSA enrichmentGHSA-8m44-j2jr-wmrp · GitHub severity HIGH · GitHub CVSS 9.6
  22. 2026-10-03 16:33 UTCEG score recompute
  23. 2026-10-03 16:33 UTCGHSA enrichmentGHSA-8m44-j2jr-wmrp · GitHub severity HIGH · GitHub CVSS 9.6
  24. 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  25. 2026-10-03 06:13 UTCGHSA enrichmentGHSA-8m44-j2jr-wmrp · GitHub severity HIGH · GitHub CVSS 9.6
  26. 2026-10-03 01:34 UTCGHSA enrichmentGHSA-8m44-j2jr-wmrp · GitHub severity HIGH · GitHub CVSS 9.6
  27. 2026-10-02 20:58 UTCEG score recompute
  28. 2026-10-02 20:58 UTCGHSA enrichmentGHSA-8m44-j2jr-wmrp · GitHub severity HIGH · GitHub CVSS 9.6
  29. 2026-10-02 15:37 UTCGHSA enrichmentGHSA-8m44-j2jr-wmrp · GitHub severity HIGH · GitHub CVSS 9.6
  30. 2026-10-02 11:03 UTCGHSA enrichmentGHSA-8m44-j2jr-wmrp · GitHub severity HIGH · GitHub CVSS 9.6
  31. 2026-10-02 06:43 UTCGHSA enrichmentGHSA-8m44-j2jr-wmrp · GitHub severity HIGH · GitHub CVSS 9.6
  32. 2026-10-02 01:24 UTCGHSA enrichmentGHSA-8m44-j2jr-wmrp · GitHub severity HIGH · GitHub CVSS 9.6
  33. 2026-10-01 21:04 UTCEG score recompute
  34. 2026-10-01 21:04 UTCGHSA enrichmentGHSA-8m44-j2jr-wmrp · GitHub severity HIGH · GitHub CVSS 9.6
  35. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  36. 2026-10-01 15:28 UTCEG score recompute
  37. 2026-10-01 15:28 UTCGHSA enrichmentGHSA-8m44-j2jr-wmrp · GitHub severity HIGH · GitHub CVSS 9.6
  38. 2026-10-01 14:19 UTCGHSA enrichmentGHSA-8m44-j2jr-wmrp · GitHub severity HIGH · GitHub CVSS 9.6
  39. 2026-10-01 09:59 UTCGHSA enrichmentGHSA-8m44-j2jr-wmrp · GitHub severity HIGH · GitHub CVSS 9.6
  40. 2026-10-01 05:38 UTCGHSA enrichmentGHSA-8m44-j2jr-wmrp · GitHub severity HIGH · GitHub CVSS 9.6
  41. 2026-10-01 01:09 UTCGHSA enrichmentGHSA-8m44-j2jr-wmrp · GitHub severity HIGH · GitHub CVSS 9.6
  42. 2026-09-30 20:19 UTCEG score recompute
  43. 2026-09-30 20:19 UTCGHSA enrichmentGHSA-8m44-j2jr-wmrp · GitHub severity HIGH · GitHub CVSS 9.6
  44. 2026-09-30 11:46 UTCGHSA enrichmentGHSA-8m44-j2jr-wmrp · GitHub severity HIGH · GitHub CVSS 9.6
  45. 2026-09-30 07:15 UTCEG score recompute
  46. 2026-09-30 07:15 UTCGHSA enrichmentGHSA-8m44-j2jr-wmrp · GitHub severity HIGH · GitHub CVSS 9.6
  47. 2026-09-29 15:24 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  48. 2026-09-29 15:15 UTCGHSA enrichmentGHSA-8m44-j2jr-wmrp · GitHub severity HIGH · GitHub CVSS 9.6
  49. 2026-09-29 06:13 UTCGHSA enrichmentGHSA-8m44-j2jr-wmrp · GitHub severity HIGH · GitHub CVSS 9.6
  50. 2026-09-29 01:53 UTCGHSA enrichmentGHSA-8m44-j2jr-wmrp · GitHub severity HIGH · GitHub CVSS 9.6
  51. 2026-09-28 21:33 UTCEG score recompute
  52. 2026-09-28 21:33 UTCGHSA enrichmentGHSA-8m44-j2jr-wmrp · GitHub severity HIGH · GitHub CVSS 9.6
  53. 2026-09-28 13:52 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  54. 2026-09-28 12:27 UTCGHSA enrichmentGHSA-8m44-j2jr-wmrp · GitHub severity HIGH · GitHub CVSS 9.6
  55. 2026-09-28 08:07 UTCGHSA enrichmentGHSA-8m44-j2jr-wmrp · GitHub severity HIGH · GitHub CVSS 9.6
  56. 2026-09-28 03:45 UTCGHSA enrichmentGHSA-8m44-j2jr-wmrp · GitHub severity HIGH · GitHub CVSS 9.6
  57. 2026-09-27 23:15 UTCGHSA enrichmentGHSA-8m44-j2jr-wmrp · GitHub severity HIGH · GitHub CVSS 9.6
  58. 2026-09-27 18:54 UTCGHSA enrichmentGHSA-8m44-j2jr-wmrp · GitHub severity HIGH · GitHub CVSS 9.6
  59. 2026-09-27 14:33 UTCEG score recompute
  60. 2026-09-27 14:33 UTCGHSA enrichmentGHSA-8m44-j2jr-wmrp · GitHub severity HIGH · GitHub CVSS 9.6
  61. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  62. 2026-09-27 10:12 UTCGHSA enrichmentGHSA-8m44-j2jr-wmrp · GitHub severity HIGH · GitHub CVSS 9.6
  63. 2026-09-27 05:52 UTCGHSA enrichmentGHSA-8m44-j2jr-wmrp · GitHub severity HIGH · GitHub CVSS 9.6
  64. 2026-09-27 00:41 UTCEG score recompute
  65. 2026-09-27 00:41 UTCGHSA enrichmentGHSA-8m44-j2jr-wmrp · GitHub severity HIGH · GitHub CVSS 9.6
  66. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.4% · 35th percentile
  67. 2026-09-26 00:28 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  68. 2026-09-25 16:52 UTCGHSA enrichmentGHSA-8m44-j2jr-wmrp · GitHub severity HIGH · GitHub CVSS 9.6
  69. 2026-09-25 09:07 UTCGHSA enrichmentGHSA-8m44-j2jr-wmrp · GitHub severity HIGH · GitHub CVSS 9.6
  70. 2026-09-25 04:47 UTCGHSA enrichmentGHSA-8m44-j2jr-wmrp · GitHub severity HIGH · GitHub CVSS 9.6
  71. 2026-09-25 00:27 UTCGHSA enrichmentGHSA-8m44-j2jr-wmrp · GitHub severity HIGH · GitHub CVSS 9.6
  72. 2026-09-24 19:48 UTCGHSA enrichmentGHSA-8m44-j2jr-wmrp · GitHub severity HIGH · GitHub CVSS 9.6
  73. 2026-09-24 15:27 UTCEG score recompute
  74. 2026-09-24 15:27 UTCGHSA enrichmentGHSA-8m44-j2jr-wmrp · GitHub severity HIGH · GitHub CVSS 9.6
  75. 2026-09-24 14:04 UTCEPSS rescoreEPSS 0.4% · 34th percentile

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-76840?
CVE-2026-76840 is a critical-severity vulnerability; its CVE record was 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 made public?
CVE-2026-76840 was made public on August 18, 2026: that is the date its CVE record's CNA, VulnCheck, gives for when the vulnerability was made public. The CVE record itself was published on August 24, 2026. EchelonGraph's copy of the record carries a last-modified date of October 1, 2026; the record at its source may have been updated since.
Is CVE-2026-76840 actively exploited?
CVE-2026-76840 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.4% probability of exploitation in the next 30 days (35th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-76840?
CVE-2026-76840 has a CVSS base score of 9.6 (the CNA's own assessment, by vulncheck; NVD's own analysis pending).
How do I remediate CVE-2026-76840?
A fix for CVE-2026-76840 is referenced (a reference tagged "Patch", often a source commit), but EchelonGraph has no release containing it on record. Check that reference and the vendor's advisory for a release that contains the fix and update to it; until then, restrict network exposure of the affected system or apply the vendor's mitigation. The vendor advisories EchelonGraph has for CVE-2026-76840 are linked in the Vendor Advisories panel on this page.

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