CVE-2026-63409

HIGHPre-NVD 8.28.2
EchelonGraph scoreMEDIUM confidence

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

This high-severity CVE scores 8.2 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.5% (37th percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.

Triggered by: Headline CVSS from a secondary CVSS source
Sources: EPSS, a secondary CVSS source
Elevated
8.2EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines at low or medium mission impact and sooner than that at high (the SSVC decision on this page).
  • CISA's Vulnrichment rates exploitation as PoC; EchelonGraph holds no exploit-code reference for it
CISA-KEV: Not listedEPSS PROB: 0.5%CVSS: 8.2Exploit: No code on recordExposed services: Not assessed

A fix is available — apply it.

Deskflow is a keyboard and mouse sharing app. From 1.17.0 until continuous build 1.26.0.296, a malicious Deskflow server can send an odd-length DSOP vector to ServerProxy::setOptions() in src/lib/client/ServerProxy.cpp, causing the missing value after the final option key to be read beyond the vector during the PacketStreamFilter::filterEvent to ServerProxy::handleData() to ServerProxy::parseHandshakeMessage() call chain and crash the connected client. This issue is fixed in continuous build 1.26.0.296.

CVSS v3
8.2
EG Score
8.2HIGHmedium confidence
EG Risk
68
EG Risk 68/100

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)
Severity82% × 45%
The EG Score, 8.2 of 10.
Exploitation40% × 40%
EchelonGraph's fixed weight for EG-KEV Tier 3 (Elevated): a constant, not a probability.
Automatability100% × 15%
CISA's SSVC Automatable value: yes (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Attend at high (mission-essential systems).
Exploitation public PoC (CISA Vulnrichment) · Automatable yes (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 available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
EPSS PROB
0.5%
EPSS %ILE
37th
KEV
Not listed

SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Attend at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.

Exploitation public PoC (CISA Vulnrichment) · Automatable yes (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)14 days if the affected system is publicly exposed; 60 days if it is not.

In CISA KEV no (CISA's KEV catalog) · Automatable yes (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 17, 2026

Last Modified

September 9, 2026

Advisory Details (2)

Auto-updated Aug 17, 2026
Patch available. Sources: github, github_commit.
GitHub commit

commit 8266fbbe6af9 (deskflow/deskflow)

Fix landed in deskflow/deskflow commit 8266fbbe6af9 — awaiting tagged release

https://github.com/deskflow/deskflow/commit/8266fbbe6af93fa370018886c7f1f35d2cee8b3f
GitHub advisoryMentions a patch (unverified)

Odd-length DSOP options vector causes out-of-bounds read in Deskflow client · Advisory · deskflow/deskflow · GitHub

https://github.com/deskflow/deskflow/security/advisories/GHSA-gmvh-3c73-m5gg

Affected Packages

(2 across 2 ecosystems)
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
deskflow1.22.0+dfsg-7 ... 1.26.0+dfsg-5 (13 versions)
  • every version on: no fix on record
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
deskflow1.22.0+dfsg-7 ... 1.26.0+dfsg-3 (11 versions)
  • every version up to 1.26.0+dfsg-4: fixed in 1.26.0+dfsg-4
—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 12× in last 7d / 48× 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.

  1. 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.5% · 37th percentile
  2. 2026-10-13 12:00 UTCEG score recompute
  3. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.5% · 37th percentile
  4. 2026-10-12 15:49 UTCEG score recompute
  5. 2026-10-11 19:33 UTCEG score recompute
  6. 2026-10-11 16:48 UTCEG score recompute
  7. 2026-10-11 14:10 UTCEG score recompute
  8. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.5% · 37th percentile
  9. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.5% · 37th percentile
  10. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.5% · 37th percentile
  11. 2026-10-08 17:13 UTCEPSS rescoreEPSS 0.5% · 37th percentile
  12. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.5% · 37th percentile
  13. 2026-10-06 21:43 UTCEG score recompute
  14. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.5% · 37th percentile
  15. 2026-10-06 09:01 UTCEG score recompute
  16. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.5% · 37th percentile
  17. 2026-10-05 06:38 UTCEG score recompute
  18. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.5% · 37th percentile
  19. 2026-10-03 17:46 UTCEG score recompute
  20. 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.5% · 37th percentile
  21. 2026-10-03 02:46 UTCEG score recompute
  22. 2026-10-02 17:56 UTCEPSS rescoreEPSS 0.5% · 37th percentile
  23. 2026-10-02 01:33 UTCEG score recompute
  24. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.5% · 36th percentile
  25. 2026-09-30 20:59 UTCEG score recompute
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  1. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.5% · 36th percentile
  2. 2026-09-30 09:58 UTCEG score recompute
  3. 2026-09-28 21:58 UTCEG score recompute
  4. 2026-09-28 13:51 UTCEPSS rescoreEPSS 0.5% · 36th percentile
  5. 2026-09-27 19:06 UTCEG score recompute
  6. 2026-09-27 08:04 UTCEG score recompute
  7. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.5% · 36th percentile
  8. 2026-09-25 01:59 UTCEG score recompute
  9. 2026-09-23 20:27 UTCEG score recompute
  10. 2026-09-23 17:54 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  11. 2026-09-22 20:38 UTCEG score recompute
  12. 2026-09-22 06:25 UTCEG score recompute
  13. 2026-09-20 20:55 UTCEG score recompute
  14. 2026-09-20 20:16 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  15. 2026-09-19 22:52 UTCEG score recompute
  16. 2026-09-18 21:55 UTCEG score recompute
  17. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  18. 2026-09-17 21:53 UTCEG score recompute
  19. 2026-09-16 23:04 UTCEG score recompute
  20. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  21. 2026-09-16 11:05 UTCEG score recompute
  22. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  23. 2026-09-15 11:42 UTCEG score recompute
  24. 2026-09-14 00:56 UTCEG score recompute
  25. 2026-09-12 15:52 UTCEG score recompute
  26. 2026-09-11 17:48 UTCEG score recompute
  27. 2026-09-11 14:53 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  28. 2026-09-11 09:37 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  29. 2026-09-10 19:45 UTCEG score recompute
  30. 2026-09-09 03:37 UTCEG score recompute
  31. 2026-09-08 22:01 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  32. 2026-09-07 16:10 UTCEG score recompute
  33. 2026-09-07 16:01 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  34. 2026-09-06 15:59 UTCEG score recompute
  35. 2026-09-06 13:47 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  36. 2026-09-05 17:56 UTCEG score recompute
  37. 2026-09-05 15:31 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  38. 2026-09-04 19:35 UTCEG score recompute
  39. 2026-09-04 08:16 UTCEG score recompute
  40. 2026-09-04 05:07 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  41. 2026-09-02 23:10 UTCEG score recompute
  42. 2026-09-02 14:12 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  43. 2026-09-02 00:23 UTCEG score recompute
  44. 2026-09-01 13:54 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  45. 2026-09-01 13:18 UTCEG score recompute
  46. 2026-09-01 04:40 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  47. 2026-08-31 04:02 UTCEG score recompute
  48. 2026-08-30 19:17 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  49. 2026-08-30 05:59 UTCEG score recompute
  50. 2026-08-30 01:22 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  51. 2026-08-29 05:22 UTCEG score recompute
  52. 2026-08-28 21:42 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  53. 2026-08-27 22:22 UTCEG score recompute
  54. 2026-08-27 14:25 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  55. 2026-08-27 00:19 UTCEG score recompute
  56. 2026-08-26 14:46 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  57. 2026-08-25 15:12 UTCEG score recompute
  58. 2026-08-25 13:49 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  59. 2026-08-24 17:07 UTCEG score recompute
  60. 2026-08-23 07:22 UTCEG score recompute
  61. 2026-08-23 00:19 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  62. 2026-08-22 09:19 UTCEG score recompute
  63. 2026-08-21 23:49 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  64. 2026-08-21 00:06 UTCEG score recompute
  65. 2026-08-20 22:55 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  66. 2026-08-20 01:50 UTCEG score recompute
  67. 2026-08-19 17:04 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  68. 2026-08-18 16:44 UTCEG score recompute
  69. 2026-08-18 15:33 UTCEG score recompute
  70. 2026-08-18 13:48 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  71. 2026-08-17 21:30 UTCEG score recompute
  72. 2026-08-17 21:05 UTCEG score recomputeFirst assessed: 8.2 HIGH
  73. 2026-08-17 21:04 UTCMITRE cvelistV5first tracked

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Frequently asked(5)

What is CVE-2026-63409?
CVE-2026-63409 is a high-severity vulnerability; its CVE record was published on August 17, 2026. Deskflow is a keyboard and mouse sharing app. From 1.17.0 until continuous build 1.26.0.296, a malicious Deskflow server can send an odd-length DSOP vector to ServerProxy::setOptions() in src/lib/client/ServerProxy.cpp, causing the missing value after the final option key to be read beyond the…
When was the CVE record for CVE-2026-63409 published?
The CVE record for CVE-2026-63409 was published on August 17, 2026. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of September 9, 2026; the record at its source may have been updated since.
Is CVE-2026-63409 actively exploited?
CVE-2026-63409 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.5% probability of exploitation in the next 30 days (37th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-63409?
CVE-2026-63409 has a CVSS base score of 8.2 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-63409?
A fix for CVE-2026-63409 is available: update to the fixed version the vendor names in its advisory.

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