CVE-2026-54069: SiYuan: Unauthenticated Admin API Access via Blanket chrome-extension:// Origin Allowlist

Should you act?

Critical and remotely reachable

No known exploitation yet, but it is network-reachable without credentials. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.

• Not in CISA KEV, but CISA’s SSVC assessment records a public proof-of-concept, so attack code exists.
• EPSS 0.6%, percentile 47: FIRST’s model estimates a 0.6% chance of exploitation activity in the next 30 days, higher than 47% of all scored CVEs (low). EPSS is a probability, not a verdict.
• Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
• Only applies if your dependency tree includes github.com/siyuan-note/siyuan/kernel (Go) < 0.0.0-20260628153353-2d5d72223df4, fixed in 0.0.0-20260628153353-2d5d72223df4. Check your lockfile, including transitive dependencies.

What it is

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.

From the GitHub advisory

Summary

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.

Affected Versions

SiYuan

Vulnerability Details

Weakness type: CWE-346.

Product: github.com/siyuan-note/siyuan/kernel (Go) · Assigned by: GitHub_M · Published: 2026-06-24

Affected and fixed versions

Severity scores

• Attack vector: network (remotely reachable)
• Attack complexity: high (needs special conditions)
• Attack requirements: none
• Privileges required: none (no login)
• User interaction: none

CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.

Exploitation and urgency

• CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
• CISA SSVC assessment: exploitation poc, automatable no, technical impact total.
• FIRST EPSS (model of 2026-10-21): 0.58% probability of exploitation activity in the next 30 days; percentile 47.

Timeline

• 2026-06-24 — CVE record published by GitHub_M
• 2026-06-25 — CVE record last updated
• 2026-07-10 — GitHub-reviewed advisory GHSA-hvr9-72v2-fff3 published (critical)

Sources and references

Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.

Vulnerability records

1. GitHub Advisory GHSA-hvr9-72v2-fff3 github.com
2. CVE.org record CVE-2026-54069 cve.org
3. NVD entry CVE-2026-54069 nvd.nist.gov

Other references from the CVE record and advisory

1. github.com github.com

Critical Go advisories · Today’s Security Digest