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CVE-2026-74868

HIGH 8.7 PoC AVAILABLE

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

SiYuan versions before 3.7.4 contain an unthrottled brute-force vulnerability in the Publish Service Basic Auth implementation (PublishServiceTransport.RoundTrip() in kernel/server/proxy/publish.go). The Publish Service runs on a separate, unauthenticated-by-default listener (default TCP port 6808) and gates named publish-viewer accounts (Conf.Publish.Auth.Accounts) with Basic Auth that has no rate limiting, per-account lockout, or backoff. Unauthenticated remote attackers can submit unlimited password guesses against named accounts to gain access to published notes/notebooks.

EXPLOIT AVAILABLE

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

Exploitation likelihood

0.4%chance of exploitation in 30 days · 31st percentile

○ In CISA KEV ● Public exploit / PoC

Impact if exploited

8.7CVSS 4.0 · HIGH

  • ConfidentialityHigh
  • IntegrityNone
  • AvailabilityNone

What an attacker needs

  • ✓Access: Reachable over the network — no local access needed
  • ✓Privileges: No account or privileges required
  • ✓User interaction: No user interaction needed
  • ✓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-2026-74868/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-2026-74868/poc.json

Affected

Vendors Siyuan Note

Products Siyuan

Weakness (CWE)

  • CWE-307: Improper Restriction of Excessive Authentication Attempts

CVSS vector

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

All CVSS metrics

  • HIGH 8.7 v4.0 · CNA Primary
    CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
  • HIGH 7.5 v3.1 · CNA Primary
    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
  • HIGH 8.7 v4.0 · NVD Secondary
    CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/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 7.5 v3.1 · NVD Secondary
    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

References

Exploits & PoC

Advisories

Sources: NVD · CVE.org · EPSS