CVE-2026-54069

CRITICAL NUCLEI

SiYuan: Unauthenticated Admin API Access via Blanket chrome-extension:// Origin Allowlist

Title source: cna
STIX 2.1

Exploitation Summary

CVE-2026-54069 has a Nuclei detection template available — see the Nuclei card below for the Shodan/FOFA recon queries.

Description

SiYuan is an open-source personal knowledge management system. Prior to 3.7.0, SiYuan Note's kernel HTTP server unconditionally trusts all chrome-extension:// origins, granting RoleAdministrator access to every installed browser extension without any authentication. Combined with the default empty AccessAuthCode on desktop installs, any Chrome/Chromium extension -- including a compromised legitimate extension via supply chain attack -- can make fully authenticated admin API calls to the SiYuan kernel at 127.0.0.1:6806, enabling data exfiltration, stored XSS injection, and configuration tampering. This vulnerability is fixed in 3.7.0.

Nuclei Templates (1)

SiYuan Note <= 3.6.5 - Authentication Bypass
HIGHby 0x_Akoko
Shodan: title:"SiYuan"
FOFA: title="SiYuan" || body="siyuan"

References (1)

Core 1
Core References

Scores

CVSS v4 9.2
EPSS 0.0062
EPSS Percentile 46.3%
CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/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

CISA SSVC

Vulnrichment
Exploitation poc
Automatable no
Technical Impact total

Details

CWE
CWE-346
Status published
Products (2)
siyuan-note/siyuan 0 - 0.0.0-20260628153353-2d5d72223df4Go
siyuan-note/siyuan < 3.7.0
Published Jun 24, 2026
Tracked Since Jun 25, 2026