What is CVE-2026-77086?

CVE-2026-77086 is a critical-severity vulnerability in Siyuan-Note Siyuan, classified under Path Traversal. CVSS score: 9.1/10. Published 2026-08-21.

How severe is CVE-2026-77086?

Critical severity. CVSS v3 base score is 9.1 out of 10.

Path Traversal in Siyuan-Note Siyuan

CVE-2026-77086

SiYuan before v3.7.4 fails to validate the packageName parameter in Bazaar install and uninstall endpoints, allowing authenticated administrators to perform path traversal via directory traversal sequences. Attackers with admin access can write arbitrary files to any location via install operations or recursively delete directories via uninstall operations by supplying crafted packageName values.

Vulnerability class: Path Traversal (Directory Traversal)

CVSS v3 metric

CVSS v3 base score 9.1 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H.

Affected products

Siyuan-note Siyuan

Weakness classification (CWE)

CWE-22 — Path Traversal

References

disclosure@vulncheck.com (vendor-advisory)
disclosure@vulncheck.com (third-party-advisory)

Frequently asked questions

What is CVE-2026-77086?: CVE-2026-77086 is a critical-severity vulnerability in Siyuan-Note Siyuan, classified under Path Traversal. CVSS score: 9.1/10. Published 2026-08-21.
How severe is CVE-2026-77086?: Critical severity. CVSS v3 base score is 9.1 out of 10.