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CVE-2026-74801

HIGH 8.6 PoC AVAILABLE

Published 2026-08-17 · Last modified 2026-08-17

SiYuan before 3.7.4 fails to properly escape workspace directory paths when constructing command-line arguments for the elevated elevator.exe helper process. Attackers can create a malicious workspace directory with command metacharacters in its path and trigger the Microsoft Defender exclusion flow to execute arbitrary commands with administrator privileges after UAC approval.

EXPLOIT AVAILABLE

Public exploit or PoC code exists. Modeled probability is still low, but the barrier to attack is reduced — watch closely.

Exploitation likelihood

0.3%chance of exploitation in 30 days · 19th percentile

○ In CISA KEV ● Public exploit / PoC

Impact if exploited

8.6CVSS 4.0 · HIGH

  • ConfidentialityHigh
  • IntegrityHigh
  • AvailabilityHigh

What an attacker needs

  • ⚠Access: Requires local access to the host
  • ⚠Privileges: Requires a low-privilege account
  • ⚠User interaction: Succeeds with passive user activity
  • ✓Complexity: No special conditions — reliably repeatable
  • ✓Requirements: No special attack requirements

✓ lowers the bar for an attacker · ⚠ raises it

Proof of concept & exploit code

Test against your own equipment

curl -s https://vulnpedia.com/cve/CVE-2026-74801/poc.jsonMachine-readable PoC index for this CVE (for automation).

Listed for defensive triage, patch verification, and authorized testing on systems you own. Machine-readable: /cve/CVE-2026-74801/poc.json

Affected

Vendors Siyuan Note

Products Siyuan

Weakness (CWE)

  • CWE-78: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')

CVSS vector

CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:P/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H

All CVSS metrics

  • HIGH 8.6 v4.0 · CNA Primary
    CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:P/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
  • HIGH 8.2 v3.1 · CNA Primary
    CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H
  • HIGH 8.6 v4.0 · NVD Secondary
    CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:P/VC:H/VI:H/VA:H/SC:H/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
  • HIGH 8.2 v3.1 · NVD Secondary
    CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H

References

Exploits & PoC

Advisories

Sources: NVD · CVE.org · EPSS