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CVE-2026-74802

N/A 0 PoC AVAILABLE

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

SiYuan versions before 3.7.4 contain a cross-site WebSocket hijacking vulnerability in the admin-only /ws/network/proxy endpoint that explicitly disables origin validation by setting CheckOrigin to unconditionally return true. Attackers can craft malicious webpages that establish WebSocket connections to this endpoint and direct the SiYuan kernel process to proxy arbitrary network traffic to attacker-chosen targets, enabling authenticated network pivoting through the victim's machine.

EXPLOIT AVAILABLE

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

Exploitation likelihood

0.1%chance of exploitation in 30 days · 1st percentile

○ In CISA KEV ● Public exploit / PoC

Impact if exploited

0CVSS 4.0 · NONE

  • ConfidentialityNone
  • IntegrityNone
  • AvailabilityNone

What an attacker needs

  • ✓Access: Reachable over the network — no local access needed
  • ⚠Privileges: Requires a low-privilege account
  • ⚠User interaction: Succeeds with passive user activity
  • ⚠Complexity: Needs a race window or specific setup
  • ⚠Requirements: Specific conditions must be present

✓ 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-2026-74802/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-2026-74802/poc.json

Affected

Vendors Siyuan Note

Products Siyuan

Weakness (CWE)

  • CWE-346: Origin Validation Error

CVSS vector

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

All CVSS metrics

  • NONE 0 v4.0 · CNA Primary
    CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:P/VC:N/VI:N/VA:N/SC:N/SI:N/SA:N
  • HIGH 8.2 v3.1 · CNA Primary
    CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:L/A:N
  • NONE 0 v4.0 · NVD Secondary
    CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:P/VC:N/VI:N/VA:N/SC:N/SI:N/SA:N/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:N/AC:L/PR:N/UI:R/S:C/C:H/I:L/A:N

References

Exploits & PoC

Advisories

Sources: NVD · CVE.org · EPSS