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CVE-2026-74867

LOW 2.3

Published 2026-08-17 · Last modified 2026-08-18

SiYuan versions before 3.7.4 contain a cross-site request forgery vulnerability in the session-cookie authentication branch of CheckAuth() that lacks Origin/Referer validation and sets no explicit SameSite attribute on session cookies. Attackers can craft malicious web pages that perform unauthorized actions on behalf of authenticated users by submitting requests with valid session cookies, relying on browser default SameSite policies rather than server-enforced protections.

NO EXPLOITATION SIGNALS

No known exploitation, public exploit, or elevated probability at this time. Track for changes.

Exploitation likelihood

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

○ In CISA KEV ○ Public exploit / PoC

Impact if exploited

2.3CVSS 4.0 · LOW

  • ConfidentialityLow
  • IntegrityLow
  • AvailabilityNone

What an attacker needs

  • ✓Access: Reachable over the network — no local access needed
  • ✓Privileges: No account or privileges required
  • ⚠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-2026-74867/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-2026-74867/poc.json

Affected

Vendors Siyuan Note

Products Siyuan

Weakness (CWE)

  • CWE-352: Cross-Site Request Forgery (CSRF)

CVSS vector

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

All CVSS metrics

  • LOW 2.3 v4.0 · CNA Primary
    CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N
  • MEDIUM 4.2 v3.1 · CNA Primary
    CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N
  • LOW 2.3 v4.0 · NVD Secondary
    CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:P/VC:L/VI:L/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
  • MEDIUM 4.2 v3.1 · NVD Secondary
    CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N

References

Advisories

Sources: NVD · CVE.org · EPSS