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CVE-2026-62204

MEDIUM 5.9

Published 2026-08-22 · Last modified 2026-08-22

SiYuan versions before v3.7.4 fail to validate that packageName matches the downloaded package content in bazaar install endpoints. Attackers with same-origin access can overwrite existing trusted plugins by supplying mismatched packageName and repoURL parameters, achieving persistence across application restarts.

NO EXPLOITATION SIGNALS

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

Exploitation likelihood

EPSS not yet scored

○ In CISA KEV ○ Public exploit / PoC

Impact if exploited

5.9CVSS 4.0 · MEDIUM

  • ConfidentialityLow
  • IntegrityHigh
  • AvailabilityLow

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: 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-2026-62204/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-2026-62204/poc.json

Affected

Vendors Siyuan Note

Products Siyuan

Weakness (CWE)

  • CWE-345: Insufficient Verification of Data Authenticity

CVSS vector

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

All CVSS metrics

  • MEDIUM 5.9 v4.0 · CNA Primary
    CVSS:4.0/AV:L/AC:H/AT:P/PR:L/UI:P/VC:L/VI:H/VA:L/SC:L/SI:H/SA:L
  • MEDIUM 6.6 v3.1 · CNA Primary
    CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:C/C:L/I:H/A:L
  • MEDIUM 5.9 v4.0 · NVD Secondary
    CVSS:4.0/AV:L/AC:H/AT:P/PR:L/UI:P/VC:L/VI:H/VA:L/SC:L/SI:H/SA:L/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 6.6 v3.1 · NVD Primary
    CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:C/C:L/I:H/A:L

Sources: NVD · CVE.org · EPSS